How Magellanic penguins feed their youngsters


This video says about itself:

Magellanic Penguins on Isla Magdalena, Chile, December 2012

During our trip to South America, we visited the Magdalena Island in Chile. It is a reserve established in 1991, home to more than 150,000 of Magellanic penguins. These penguins make this spot on the shoreline of the Strait of Magellan their home. They return annually to this place between October and March to lay eggs and raise their youngsters.

Magellanic Penguins are often seen performing the “ecstatic display”. This can either be part of the mating ritual or can merely be indicative of territory ownership. Birds performing this display stretch their neck and point their beaks skywards whilst spreading their wings and making a braying noise. The display is often performed repetitively over periods of up to an hour or more.”

From the University of Washington in the USA:

Parents don’t pick favorites, at least if you’re a Magellanic penguin

February 14, 2019

Summary: Researchers wanted to know how Magellanic penguin parents in South America balance the dietary demands of multiple chicks. They found that when a Magellanic penguin parent returns to its nest with fish, the parent tries to feed each of its two chicks equal portions of food, regardless of the youngsters’ differences in age or size.

Parenthood can be a struggle, particularly for families with multiple children in need of care, nurturing, protection and attention. But a weary mom or dad may find solace in the reassurance that all parents with several offspring face a similar challenge — even the non-human variety.

Researchers at the University of Washington wanted to know how Magellanic penguin parents in South America balance the dietary demands of multiple chicks. As they report in a paper published Jan. 23 in the journal Animal Behaviour, when a Magellanic penguin parent returns to its nest with fish, the parent tries to feed each of its two chicks equal portions of food, regardless of the youngsters’ differences in age or size.

This finding surprised the team, since parents across the animal kingdom, including other penguin species, often allocate resources unequally to their chicks based on factors like offspring age, body condition, health and behavior, said senior author P. Dee Boersma. Boersma, a UW professor of biology and director of the Center for Ecosystem Sentinels, has for more than three decades studied penguins at Punta Tombo, a coastal region in Argentina that hosts one of this species’ largest breeding colonies.

“This is an exciting finding because, among animals, it is very unusual for parents to divide food equally among their offspring,” said Boersma. “This makes Magellanic penguin parents stand out not just among penguins, but also animals in general.”

Magellanic chicks are the same size when they hatch, but eggs within a nest hatch at different times. After mating, a Magellanic female lays two eggs about four days apart. One chick typically hatches at least two days before the other. Chicks grow to different sizes based on the timing of their first feedings. By the time both chicks are at least 20 days old, one chick is on average 22 percent heavier than its sibling, the team found. Yet despite these size differences, this study shows that when Magellanic chicks are older and more mobile, parents feed both chicks equally as well as rapidly.

“These findings raise some very interesting evolutionary questions about how and why this behavior — feeding chicks equally — arose,” said Boersma.

For this study, Boersma and her team observed parents feeding their chicks at Punta Tombo from 2003 to 2007. Past research showed that parents alternate roles when chicks are small: One stays at the nest to guard chicks while the other feeds offshore and brings back a belly full of fish to regurgitate into the chicks’ mouths. For this study, the researchers observed nests where the chicks were at least 20 days old to track whether chick behaviors, such as begging or competition during feeding, influenced the amount of food they received. The team weighed 218 chicks both before and after the feeding, and observed parent and offspring behavior during mealtime. Forty chicks came from one-chick nests — presumably cases where the second egg failed to hatch or the chick died of starvation — while the other 178 came from 89 two-chick nests.

As expected, chicks without a sibling received more food during a feeding and were heavier than chicks with a sibling. Before eating, singleton chicks weighed an average of about 5.7 pounds and received about 1.2 pounds of food on average per feeding. For two-chick nests, the heavier and lighter chicks weighed an average of 5.1 pounds and 4.2 pounds, respectively. Yet both chicks received about 0.8 pounds of food on average per feeding.

Parents with two chicks managed this equal division despite the rushed choreography of mealtimes. The researchers found that feedings lasted just 21 minutes on average, during which the parent used its flippers to keep one chick to its left and one to its right — turning its head to feed one and then the other. Light and heavy chicks begged a similar number of times and each switched sides five or six times during the feeding, yet siblings did not act aggressively toward one other. The researchers observed that the parent directed more non-feeding behaviors to the lighter chick, such as opening its mouth but not regurgitating any food. Yet ultimately the lighter chick received the same amount of food as its sibling.

These findings shed light on when, where and how animals decide whether to treat their offspring equally or give preferential attention to one. For Magellanic penguins, factors affecting this behavior may be food supply, digestion and the time between feedings. In other penguin species, food supply impacts feeding behaviors. Adélie penguins, for example, have a relatively stable and abundant food supply because long daylight hours in Antarctic summers allow them to feed around the clock. Boersma and her colleague Lloyd Davis at the University of Otago in New Zealand found that Adélie parents run from their chicks, and the chick that follows its parent the longest is typically fed the most. For Magellanic penguins, food is less plentiful, and chicks typically wait three to five days between feedings. Each year, about 40 percent of chicks die at Punta Tombo due to starvation, and research by Boersma’s group indicates that a chick is most at risk of starvation when it is between 5 and 9 days old. Magellanic parents are prompted feed chicks as soon as they arrive at the nest because food that digests too long in their stomachs is less nutritious for chicks.

These factors may pressure adults to feed chicks quickly and equally, Boersma said. In addition, chicks may avoid direct competition because that could delay the feeding, she added. The age of the chicks in this study — all at least 20 days old — may also help explain their findings.

“This behavior may have evolved because, once both chicks reach this age, it may be advantageous for the parents to try to raise both of their chicks to fledging — the stage at which chicks leave the nest — rather than preferentially giving one more resources than the other,” said Boersma.

If so, then equality on the part of Magellanic penguin parents is less of an egalitarian virtue and more an investment in survival of the next generation.

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How sea snakes avoid predators


This 2015 video says about itself:

Many people don’t realize that there are snakes that live in the ocean. And believe it or not, they’re actually considerably more venomous than land snakes! Jonathan travels to Australia and the Philippines to find these marine reptiles, and learns why they are almost completely harmless to divers.

From the University of Adelaide in Australia:

‘Seeing’ tails help sea snakes avoid predators

February 15, 2019

New research has revealed the fascinating adaptation of some Australian sea snakes that helps protect their vulnerable paddle-shaped tails from predators.

An international study led by the University of Adelaide shows that several species of Australian sea snakes can sense light on their tail skin, prompting them to withdraw their tails under shelter. The study has also produced new insights into the evolution and genetics of this rare light sense.

The researchers found that olive sea snakes (Aipysurus laevis) and other Aipysurus species move their tail away from light. They believe this is an adaptation to keep the tail hidden from sharks and other predators.

“Sea snakes live their entire lives at sea, swimming with paddle-shaped tails and resting at times during the day under coral or rocky overhangs,” says study lead author Jenna Crowe-Riddell, PhD candidate in the University of Adelaide’s School of Biological Sciences. “Because sea snakes have long bodies, the tail-paddle is a large distance from the head, so benefits from having a light-sense ability of its own.

“The olive sea snake was the only reptile, out of more than 10,000 reptile species, that was known to respond to light on the skin in this way.”

The researchers tested for light-sensitive tails in eight species of sea snakes, but found that only three species had the light-sense ability. They concluded the unique ability probably evolved in the ancestor of just six closely related Australian species.

“There are more than 60 species of sea snake so that’s less than 10% of all sea snakes,” says Ms Crowe-Riddell. “We don’t know why this rare sense has evolved in just a few Aipysurus species.”

The researchers used RNA sequencing to see what genes are active in the skin of sea snakes. They discovered a gene for a light-sensitive protein called melanopsin, and several genes that are involved in converting light into information in the nervous system.

“Melanopsin is used in a range of genetic pathways that are linked to sensing overall light levels around us. It is even used by some animals, including humans, for regulating sleep cycles and in frogs to change their skin colour as a camouflage,” says Ms Crowe-Riddell.

Lead scientist Dr Kate Sanders, ARC Future Fellow at the University of Adelaide, says: “We’ve confirmed the ability of olive sea snakes to sense light in their tails and found the same ability in two other species. We’ve identified a shortlist of genes that are likely to be involved in detecting light. But further study will be needed to target these genes before we can really understand the genetic pathways involved in this fascinating behaviour.”

Orangutan tool use, new study


This 2009 videp is called Attenborough: Amazing DIY Orangutans | BBC Earth.

From the University of Vienna in Austria:

Orangutans make complex economic decisions about tool use

February 14, 2019

Flexible tool use is closely associated to higher mental processes such as the ability to plan actions. Now a group of cognitive biologists and comparative psychologists from the University of Vienna, the University of St Andrews and the University of Veterinary Medicine Vienna that included Isabelle Laumer and Josep Call, has studied tool related decision-making in a non-human primate species — the orangutan. They found that the apes carefully weighed their options: eat an immediately available food reward or wait and use a tool to obtain a better reward instead? To do so the apes considered the details such as differences in quality between the two food rewards and the functionality of the available tools in order to obtain a high quality food reward, even when multidimensional task components had to be assessed simultaneously.

Tool-use in animals is rare and often quickly rated as intelligent due to its striking nature. For instance, antlions throw small pebbles at potential prey, archer fish down prey by spitting water at them, and sea otters use stones to crack open shells. Nevertheless, most types of tool use are quite inflexible, typically applied to one situation and tightly controlled by processes that are a part of the respective animal’s inborn behavioural repertoire. In contrast, intelligent tool use requires the integration of multiple sources of information to flexibly adapt to quickly changing environmental conditions.

Orangutans share 97 percent of their DNA with us and are among the most intelligent and most endangered primates. They have human-like long-term memory, routinely use a variety of sophisticated tools in the wild and construct elaborate sleeping nests each night from foliage and branches. In their natural habitat, the evergreen rainforests of Borneo and Sumatra, orangutans have to consider several factors simultaneously, such as the predictability to find ripe fruits, the distance and reachability of food as well as the available tools to open extractable food sources. So far it was unknown how orangutans adapt their decisions when the use of a tool is involved and how many factors they can process at the same time in order to make profitable decisions.

Researchers from the University of Vienna, the University of Veterinary Medicine Vienna and the University of St Andrews investigated for the first time how orangutans adapt their decisions when the use of a tool is involved and how many factors they can process at the same time in order to make profitable decisions at the Wolfgang Koehler Primate Research Center in Leipzig.

The researchers used two different types of food items: Banana-pellets, which are the orangutans’ most favourite food type, and apple pieces which they like but disregard if banana-pellets are available. They could extract these items from two different apparatuses: an apparatus required probing with a stick tool to obtain the food item while the other required dropping a ball inside it. Each apparatus could only be operated with the respective tool. During testing, orang-utans were confronted with either one or two baited apparatus/es and a choice between two items (usually a food item and a tool). Once the apes had picked one item the other was immediately removed.

Orangutans flexibly adapted their decisions to different conditions: “If the apple piece (likeable food) or the banana-pellet (favourite food) was out of immediate reach inside the apparatus and the choice was between an immediate banana-pellet and a tool, they chose the food over the tool, even when the tool was functional for the respective apparatus,” explains Isabelle Laumer who conducted the experiment. “However, when the orangutans could choose between the apple-piece and a tool they chose the tool but only if it worked for the available apparatus: For example when the stick and the likeable food was available but the apes faced the ball-apparatus baited with the favourite banana-pellet, they chose the apple-piece over the non-functional tool. However when the stick-apparatus with the banana-pellet inside was available they chose the stick-tool over the immediate apple-piece,” she further explains. “In a final task, that required the orangutans to simultaneously focus on the two apparatuses, one baited with the banana-pellet and the other with the apple and the orangutans had to choose between the two tools they were still able to make profitable decisions by choosing the tool that enabled them to operate the apparatus with the favorite food.”

These results are similar to findings in Gofffin cockatoos that have been previously tested in the same task. “Similar to the apes, the cockatoos could overcome immediate impulses in favor of future gains even if this implied tool use. “The birds were confronted with the choice between a tool to retrieve an out-of-reach food item and an immediate reward. We found that they, similar to the apes, were highly sensible to the quality of the immediate relative to the out-of-reach reward at the same time as to whether the available tool would actually work with the task at hand,” explains Alice Auersperg, the head of the Goffin Lab in Austria. She continues: “Again, this suggests that similar cognitive abilities can evolve independently in distantly related species.”Nevertheless, the cockatoos did reach their limit at the very last task in which both apparatuses baited with both possible food qualities and both tools were available at the same time.”

“Optimality models suggest that orangutans should flexibly adapt their foraging decisions depending on the availability of high nutritional food sources, such as fruits,” says Josep Call from the University of St Andrews. “Our study shows that orangutans can simultaneously consider multi-dimensional task components in order to maximize their gains and it is very likely that we haven´t even reached the full extent of their information processing capabilities.”

“According to a 2007 survey by the United Nations Environment Program (UNEP) orangutans will be extinct in the wild within two decades if current deforestation trends continue,” says Isabelle Laumer. “Habitat loss due to extensive palm-oil production is the major threat. Unfortunately palm oil is still the most widely used vegetable oil in the world. As long as there is a demand for palm oil and we keep buying products that contain palm oil, more and more of the rainforest will be destroyed. Each of us can positively impact the survival of these extraordinary animals by making purchase decisions that may appear small, but that can collectively make a huge impact on our planet.”

New dinosaur species discovery in Tanzania


Mnyamawamtuka moyowamkia reconstruction by Mark Witton

From Ohio University in the USA:

New dinosaur with heart-shaped tail provides evolutionary clues for African continent

Mnyamawamtuka moyowamkia fossils recovered from East African Rift System

February 13, 2019

A new dinosaur that wears its “heart” on its tail provides new clues to how ecosystems evolved on the African continent during the Cretaceous period according to researchers at Ohio University.

The OHIO team identified and named the new species of dinosaur in an article published this week in PLOS ONE. The new dinosaur, the third now described from southwestern Tanzania by the NSF-funded team, is yet another member of the large, long-necked titanosaur sauropods. The partial skeleton was recovered from Cretaceous-age (~100 million years ago) rocks exposed in a cliff surface in the western branch of the great East African Rift System.

The new dinosaur is named Mnyamawamtuka moyowamkia (Mm-nya-ma-wah-mm-too-ka mm-oh-yo-wa-mm-key-ah), a name derived from Swahili for “animal of the Mtuka (with) a heart-shaped tail” in reference to the name of the riverbed (Mtuka) in which it was discovered and due to the unique shape of its tail bones.

The initial discovery of Mnyamawamtuka took place in 2004, when part of the skeleton was discovered high in a cliff wall overlooking the seasonally dry Mtuka riverbed, with annual excavations continuing through 2008. “Although titanosaurs became one of the most successful dinosaur groups before the infamous mass extinction capping the Age of Dinosaurs, their early evolutionary history remains obscure, and Mnyamawamtuka helps tell those beginnings, especially for their African-side of the story,” said lead author Dr. Eric Gorscak, a recent Ph.D. graduate of Ohio University, current research associate at the Field Museum of Natural History (Chicago) and new assistant professor at the Midwestern University in Downers Grove, just outside of Chicago. “The wealth of information from the skeleton indicates it was distantly related to other known African titanosaurs, except for some interesting similarities with another dinosaur, Malawisaurus, from just across the Tanzania-Malawi border,” noted Dr. Gorscak.

Titanosaurs are best known from Cretaceous-age rocks in South America, but other efforts by the team include new species discovered in Tanzania, Egypt, and other parts of the African continent that reveal a more complex picture of dinosaurian evolution on the planet. “The discovery of dinosaurs like Mnyamawamtuka and others we have recently discovered is like doing a four-dimensional connect the dots,” said Dr. Patrick O’Connor, professor of anatomy at Ohio University and Gorscak’s advisor during his Ph.D. research. “Each new discovery adds a bit more detail to the picture of what ecosystems on continental Africa were like during the Cretaceous, allowing us to assemble a more holistic view of biotic change in the past.”

The excavation process spanned multiple years, and included field teams suspended by ropes and large-scale mechanical excavators to recover one of the more complete specimens from this part of the sauropod dinosaur family tree. “Without the dedication of several field teams, including some whose members donned climbing gear for the early excavations, the skeleton would have eroded away into the river during quite intense wet seasons in this part of the East African Rift System,” added O’Connor.

“This latest discovery is yet another fine example of how Ohio University researchers work the world over in their pursuit of scientific research,” Ohio University President M. Duane Nellis said. “This team has turned out a number of notable discoveries which collectively contribute significantly to our understanding of the natural world.”

Mnyamawamtuka and the other Tanzanian titanosaurs are not the only animals discovered by the research team. Remains of bizarre relatives of early crocodiles, the oldest evidence for “insect farming”, and tantalizing clues about the early evolution of monkeys and apes have been discovered in recent years. Such findings from the East African Rift provide a crucial glimpse into ancient ecosystems of Africa and provide the impetus for future work elsewhere on the continent.

“This new dinosaur gives us important information about African fauna during a time of evolutionary change,” said Judy Skog, a program director in the National Science Foundation’s Division of Earth Sciences, which funded the research. “The discovery offers insights into paleogeography during the Cretaceous. It’s also timely information about an animal with heart-shaped tail bones during this week of Valentine’s Day.”

Recent findings by the research team in the Rukwa Rift Basin include:

· Shingopana songwensis — titanosaurian sauropod dinosaur, Rukwa Rift Basin

· Rukwatitan bisepultus — titanosaurian sauropod dinosaur, Rukwa Rift Basin

· Pakasuchus kapilimai — mammal-like crocodile, Rukwa Rift Basin

· Early evidence for monkey-ape split, Rukwa Rift Basin Project

· Early evidence of insect farming — Fossil Termite Nests, Rukwa Rift Basin

“The Tanzanian story is far from over but we know enough to start asking what paleontological and geological similarities and dissimilarities there are with nearby rock units. Revisiting Malawi is my top priority to address these broader, regional questions,” said Gorscak, who also participates in ongoing projects in Egypt and Kenya. “With Mnyamawamtuka and other discoveries, I’m not sure to view it as writing or reading the next chapters in the paleontological book of Africa. I’m just excited to see where this story is going to take us.”

Megalodon and great white shark updates


Megalodon extinction timeline, credit: Robert Boessenecker

From the University of Wisconsin Oshkosh in the USA:

Giant ‘megalodon‘ shark extinct earlier than previously thought

Prehistoric beast not killed off by a supernova

February 13, 2019

Summary: ‘Megalodon‘ — a giant predatory shark that has inspired numerous documentaries, books and blockbuster movies — likely went extinct at least one million years earlier than previously thought, according to new research. This is a substantial adjustment as it means that O. megalodon likely went extinct long before a suite of strange seals, walruses, sea cows, porpoises, dolphins and whales all disappeared sometime about 1-2.5 million years ago.

Megalodon — a giant predatory shark that has inspired numerous documentaries, books and blockbuster movies — likely went extinct at least one million years earlier than previously thought, according to new research published Feb. 13 in PeerJ — the Journal of Life and Environmental Sciences.

Earlier research, which used a worldwide sample of fossils, suggested that the 50-foot-long, giant shark Otodus megalodon went extinct 2.6 million years ago. Another recent study attempted to link this extinction (and that of other marine species) with a supernova known to have occurred at about this time.

However, a team of researchers led by vertebrate paleontologist Robert Boessenecker with the College of Charleston, Charleston, South Carolina, noted that in many places there were problems with the data regarding individual fossils in the study estimating the extinction date.

In the new study, the researchers reported every fossil occurrence of O. megalodon from the densely sampled rock record of California and Baja California (Mexico) in order to estimate the extinction.

Besides Boessenecker, the research team included Dana Ehret, of New Jersey State Museum; Douglas Long, of the California Academy of Sciences; Morgan Churchill, of the University of Wisconsin Oshkosh; Evan Martin, of the San Diego Natural History Museum; and Sarah Boessenecker, of the University of Leicester, United Kingdom.

They found that genuine fossil occurrences were present until the end of the early Pliocene epoch, 3.6 million years ago. All later fossils either had poor data provenance and likely came from other fossil sites or showed evidence of being eroded from older deposits. Until 3.6 million years ago, O. megalodon had a continuous fossil record on the West Coast.

“We used the same worldwide dataset as earlier researchers but thoroughly vetted every fossil occurrence, and found that most of the dates had several problems-fossils with dates too young or imprecise, fossils that have been misidentified, or old dates that have since been refined by improvements in geology; and we now know the specimens are much younger,” Boessenecker said.

“After making extensive adjustments to this worldwide sample and statistically re-analyzing the data, we found that the extinction of O. megalodon must have happened at least one million years earlier than previously determined.”

This is a substantial adjustment as it means that O. megalodon likely went extinct long before a suite of strange seals, walruses, sea cows, porpoises, dolphins and whales all disappeared sometime about 1-2.5 million years ago.

“The extinction of O. megalodon was previously thought to be related to this marine mass extinction-but in reality, we now know the two are not immediately related,” Boessenecker said.

It also is further unclear if this proposed mass extinction is actually an extinction, as marine mammal fossils between 1 and 2 million years old are extraordinarily rare-giving a two-million- year-long period of “wiggle room.”

“Rather, it is possible that there was a period of faunal turnover (many species becoming extinct and many new species appearing) rather than a true immediate and catastrophic extinction caused by an astronomical cataclysm like a supernova,” Boessenecker said.

The researchers speculate that competition with the newly evolved modern great white shark (Carcharodon carcharias) is a more likely reason for megalodon’s extinction.

Great whites first show up with serrated teeth about 6 million years ago and only in the Pacific; by 4 million years ago, they are finally found worldwide.

“We propose that this short overlap (3.6-4 million years ago) was sufficient time for great white sharks to spread worldwide and outcompete O. megalodon throughout its range, driving it to extinction-rather than radiation from outer space,” Boessenecker said.

A new study has documented unexpected consequences following the decline of great white sharks from an area off South Africa. The study found that the disappearance of great whites has led to the emergence of sevengill sharks, a top predator from a different habitat. A living fossil, sevengill sharks closely resemble relatives from the Jurassic period, unique for having seven gills instead of the typical five in most other sharks: here.

American red squirrels’ food caches, new study


This September 2014 video from the USA says about itself:

Red Squirrel Cache

One of the best things on campus happened today (well at least so far).

I was on my way back from dropping off my application to graduate and I passed by some bike racks. There was a squirrel on top of a bike, poking its head and pawing around a bag that was attached to a bike. Great, we have klepto-squirrels on campus.

But then the squirrel jumped off of the bike, down to the ground, picked up a pine cone, and then scampered back up to the bike and hid the pine cone inside the bag. This went on for about five minutes or so.

Whoever owns that bike is going to be very, very confused, and that silly squirrel is going to wonder where the hell all of his pine cones went.

From the University of Guelph in Canada:

In the squirrel world, prime real estate is determined by previous owner, study reveals

February 13, 2019

Summary: Researchers found that if a squirrel inherits territory from a male rather than a female, it will have about 1,300 more cones in its midden. This stored energy will keep the squirrel alive an extra 17 days. For females it means she will have enough food to breed earlier, resulting in her offspring leaving the nest earlier. This shows how the behavior of a complete stranger can impact the genetic contribution of another.

A young squirrel lucky enough to take over territory from an adult male squirrel is like a teenager falling into a big inheritance, according to a new University of Guelph study.

Researchers found male squirrels store more food than females, and if a young squirrel leaving the nest nabs a storage spot previously owned by a male squirrel, they will increase their lifetime pup production by 50 per cent.

“It’s like buying a home and finding a big pile of money buried in the walls,” said integrative biology professor Andrew McAdam, who worked on the study with lead author David Fisher, a former U of G post doc. “The previous owner of where you live can significantly impact how well off you are, at least in the squirrel world.”

Published in the journal Ecology Letters, the study involved hundreds of North American red squirrels.

It is part of the Kluane Red Squirrel Project, a long-term study in the Yukon investigating the ecology and evolution of red squirrels. Started by the University of Alberta in 1987, the project brings together scientists from several universities, including the University of Guelph, University of Michigan, and University of Saskatchewan to monitor behaviour and reproduction of hundreds of individually marked squirrels.

For this study, Fisher and colleagues measured the food stores and reproductive outcome of young squirrels that took over real estate previously owned by either males or females who disappeared.

Squirrels collect spruce cones in the fall and store them in the ground in a “midden” for winter. A hoard can contain more than 20,000 cones, and they can remain edible for several years, said Fisher.

“Good thing too, because spruce trees produce cones in boom-bust patterns. There are more bust than boom years, so if squirrels don’t store enough in the boom years they won’t have enough food to survive the bust years.”

It’s common for squirrels to take over the territories of other squirrels after they die and in taking over another squirrel’s territory, they also inherit their food stores, added Fisher.

“We have seen a food store last as long as 31 years — as long as we have been studying these squirrels — and owned by 13 different squirrels over that time period,” said McAdam.

In this study, researchers found that if a squirrel inherits its territory from a male rather than a female, it will have around 1,300 more cones on average in its midden. This stored energy will keep the squirrel alive for an extra 17 days.

The study also revealed that squirrels at their prime, which is three to four years old, have more cones than younger and older squirrels. This difference means squirrels that inherit their territory from a squirrel that died in mid-age inherit a larger cone store than those that inherit from a young or old squirrel.

“If a female squirrel is lucky enough to take over this prime real estate, then she will have lots of food, which allows her to breed earlier,” said McAdam. “This means her offspring will leave the nest early and they will have improved survival rates. Essentially, it will improve this squirrel’s genetic contribution to the next generation.”

These finding show how the behavior of one squirrel can impact the genetic contribution to the population of another squirrel they have never met, said Fisher.

“Ultimately, the food hoarding behaviour of a squirrel you have never met, and that may have even died before you were born, can impact your chances of survival.”