Extinct giant dormouse, new research

An artist’s impression of the giant dormouse Leithia melitensis (left) and its nearest living relative the garden dormouse (right). Image credit: James Sadler, University of York

From the University of York in England:

Skull of two million year-old giant dormouse reconstructed

July 9, 2020

A PhD student has produced the first digital reconstruction of the skull of a gigantic dormouse, which roamed the island of Sicily around two million years ago.

In a new study, the student from Hull York Medical School, has digitally pieced together fossilised fragments from five giant dormouse skulls to reconstruct the first known complete skull of the species.

The researchers estimate that the enormous long-extinct rodent was roughly the size of a cat, making it the largest species of dormouse ever identified.

The digitally reconstructed skull is 10 cm long — the length of the entire body and tail of many types of modern dormouse.

PhD student Jesse Hennekam said: “Having only a few fossilised pieces of broken skulls available made it difficult to study this fascinating animal accurately. This new reconstruction gives us a much better understanding of what the giant dormouse may have looked like and how it may have lived.”

The enormous prehistoric dormouse is an example of island gigantism — a biological phenomenon in which the body size of an animal isolated on an island increases dramatically.

The palaeontological record shows that many weird and wonderful creatures once roamed the Italian islands. Alongside the giant dormouse, Sicily was also home to giant swans, giant owls and dwarf elephants.

Jesse’s PhD supervisor, Dr Philip Cox from the Department of Archaeology at the University of York and Hull York Medical School, said: “While island dwarfism is relatively well understood, as with limited resources on an island, animals may need to shrink to survive, the causes of gigantism are less obvious.

“Perhaps, with fewer terrestrial predators, larger animals are able to survive as there is less need for hiding in small spaces, or it could be a case of co-evolution with predatory birds where rodents get bigger to make them less vulnerable to being scooped up in talons.”

Jesse spotted the fossilised fragments of skull during a research visit to the Palermo Museum in Italy, where a segment of rock from the floor of a small cave, discovered during the construction of a motorway in northwest Sicily in the 1970s, was on display.

“I noticed what I thought were fragments of skull from an extinct species embedded in one of the cave floor segments,” Jesse said. “We arranged for the segment to be sent to Basel, Switzerland for microCT scanning and the resulting scans revealed five fragmented skulls of giant dormice present within the rock.”

The reconstruction is likely to play an important role in future research directed at improving understanding of why some small animals evolve larger body sizes on islands, the researchers say.

“The reconstructed skull gives us a better sense of whether the giant dormouse would have looked similar to its normal-sized counterparts or whether its physical appearance would have been influenced by adaptations to a specific environment,” Jesse explains.

“For example, if we look at the largest living rodent — the capybara — we can see that it has expanded in size on a different trajectory to other species in the same family.”

Jesse is also using biomechanical modelling to understand the feeding habits of the giant dormouse.

“At that size, it is possible that it may have had a very different diet to its smaller relatives,” he adds.

Guinea pigs, new research

This 2013 video says about itself:

Wild Guinea Pigs (Cavia aperea)

Wild Guinea Pigs running wild around the car park on the Brazilian side of Iguassu falls.

From the University of Otago in New Zealand:

Origins of the beloved guinea pig

June 16, 2020

New University of Otago research sheds light on guinea pig domestication and how and why the small, furry animals became distributed around the world.

Just published in the international science journal, Scientific Reports, the researchers use ancient DNA from archaeological guinea pig remains which reveals the transition from the animals being used as a wild food source 10,000 years ago to their domestication and later role as beloved pets and medical animal models.

It builds on previous research over many years by Professor of Biological Anthropology, Lisa Matisoo-Smith, tracing the DNA from plants and animals that Pacific settlers carried in their canoes and using that as a proxy for identifying human population origins and tracking their movement around the Pacific.

As part of her Otago Master’s thesis research in Professor Matisoo-Smith’s lab, Edana Lord, now at Stockholm University, Sweden and Dr Catherine Collins from Otago’s Department of Anatomy and other international researchers, set about finding out where the guinea pigs that were introduced to the islands of the Caribbean came from.

Professor Matisoo-Smith explains it is generally accepted that modern guinea pigs were domesticated in the Andes region of what is now Peru. As an important food item that was also included in religious ceremonies, they were transported and traded around South America.

Sometime around AD500, guinea pigs were taken out to the islands of the Caribbean, through at least one of several established trade networks. The researchers expected that the guinea pigs found in the Caribbean would came from Colombia, one of the closer locations in South America to the Caribbean.

Using ancient DNA of guinea pigs remains excavated from several sites in the Caribbean, Peru, Colombia, Bolivia, Europe and North America, they found the guinea pigs on the islands did not originate in Colombia, but most likely originated in Peru.

What was a bigger surprise to the team was that the guinea pig remains found in the Colombian Highlands appeared to be from a totally different species. This suggests that guinea pig domestication likely took place independently in both Peru and Colombia.

The genetic information, along with archaeological contexts, also shows how the guinea pigs had different roles through time.

“They were and still are important food item in many parts of South America and cultures that derived from South America — people took them live to introduce to new islands where they were not native or they traded them for other goods,” Professor Matisoo-Smith explains.

“The guinea pig was brought to Europe in the late 1500s or early 1600s by the Spanish and to North America in the early 1800s as part of the exotic pet trade. In the 18th century, guinea pigs began to be used by medical researchers as laboratory animals because they have many biological similarities to humans, thus the origin of the phrase ‘being a guinea pig‘ in research.

“All guinea pigs today — pets, those that are sold for meat in South America and Puerto Rico, and those used in medical research — are derived from the Peruvian domesticated guinea pigs.”

Why the guinea pig was viewed as a pet in some cultures and a food source in others can likely be attributed to long-established cultural notions of what is acceptable as food.

Professor Matisoo-Smith says the research demonstrates that the history of guinea pigs is more complex than previously known and has implications for other studies regarding mammal domestication, translocation and distribution.

“Identifying the origins of the guinea pig remains from the Caribbean helps us to understand how the human trade networks in the region moved in the past 1000 years or so.

“Through this analysis of ancient guinea pig DNA, we better understand the history of human social interactions over thousands of years and across three continents. It also provides a critical historical perspective of the genetic diversity in guinea pigs and the relationship humans have had with this important domestic animal.”

How beavers benefit other wildlife

This 24 January 2020 video from Scotland says about itself:

Did you know that beavers have a ripple effect on the biodiversity of their habitat? The way they change and manage the landscape creates a haven for wildlife and the ecosystem as a whole, including small mammals, birds of prey, plants, trees and lichens, invertebrates and water-dwellers. Thanks again to Louise Ramsay and the Bamff Estate in Perthshire.

A film for WoodlandsTV by Jemma Cholawo.

From the University of Eastern Finland:

Beavers are diverse forest landscapers

June 10, 2020

Beavers are ecosystem engineers that cut down trees to build dams, eventually causing floods. Beaver-induced floods make forest landscapes and habitats increasingly diverse, but very little is known about the long-term effects of beavers on European landscapes. Researchers at the University of Eastern Finland and the University of Helsinki examined the history and occurrence of beaver-induced floods and patch dynamics in southern Finland. They used a unique dataset of field observations from 1970 to 2018.

Floods caused by beavers over the course of history form a network of different habitats that remain interconnected even for long periods of time.

“Beavers can help to restore wetland ecosystems and entire boreal forests, and they also help in conserving the biodiversity of these environments,” Researcher Sonja Kivinen from the University of Eastern Finland says.

The European beaver was hunted to extinction in the 19th century Finland. Nowadays, the study area is home to the American beaver, which was introduced there in the 1950s. The American beaver builds similar dams as the European one.

“The spread of the beaver in our study area has created a diverse and constantly changing mosaic of beaver ponds and beaver meadows of different ages,” Kivinen says.

In 49 years, the number of beaver-induced flood sites grew 11-fold.

The researchers observed that the number of beaver-induced flood sites grew by more than 11-fold over the study period. In addition to creating new flood sites, beavers also often use old sites to cause new floods. The duration of an individual flood and the frequency of floods can vary greatly between different flood sites, resulting in an abundance of habitat patches with different environmental conditions.

“Thanks to beaver activity, there is a unique richness of wetlands in the forest landscape: flowages dominated by bushes, beaver meadows, and deadwood that can be used by various other species,” University Lecturer Petri Nummi from the University of Helsinki says.

Indeed, beaver-induced disturbances are more predictable in diversifying the forest landscape than for example forest fires or storms.

North American muskrat decline, why?

This 2016 video from Wyoming in the USA says about itself:

Muskrats are a native aquatic mammal found throughout Wyoming. They look similar to beavers, but are generally smaller and have narrower tails.

From Penn State University in the USA:

Many factors may contribute to steep, decades-long muskrat population drop

June 8, 2020

Muskrat populations declined sharply across North America over the last 50 years or so, and wildlife scientists have struggled to understand why. A Pennsylvania research team investigated whether pathogens, parasites, environmental contaminants and disease may be contributing to this decline.

Trappers saw steep declines in muskrat harvest throughout the animal’s native range, with decreases exceeding 50% in some states, according to David Walter, Penn State adjunct assistant professor of wildlife ecology in the College of Agricultural Sciences. In Pennsylvania, for example, according to the state Game Commission, the muskrat harvest declined from 720,000 in 1983 to 58,295 in 2010.

“Some of that decline can be attributed to a reduction in trapping activity, but clearly the muskrat population is significantly smaller than it used to be,” he said. “A number of theories to explain the widespread muskrat declines have been proposed, including habitat loss, predation, environmental contamination and diseases. In this study, we examine a number of those possibilities.”

To analyze trends in muskrat mortality, researchers pored over 131 articles, published from 1915 to 2019, from 27 U.S. states and nine Canadian provinces that contained information about muskrat exposure to diseases and contaminants and mortality events. Information collected from articles included; year of survey; location of survey; methodology; number of animals surveyed; pathogen or contaminant identities; and the presence or absence of associated disease, as evidenced by reported clinical signs or lesions.

Among the common factors reported associated with muskrat infections or mortality in some cases were: viruses including canine distemper virus, rabies and Aleutian mink disease virus; a variety of fungal infections; ailments such as tularemia and Tyzzer’s disease; cyanobacteria, possibly indicating the presence of toxic algae; parasites including protozoans, trematodes, cestodes, nematodes and ectoparasites such as ticks; toxins, including heavy metals from industrial discharges and lead from ammunition deposits; and agricultural-related contaminants including pesticides, herbicides and insecticides.

Because of the wide range of differences in how the many authors had collected information about the factors in muskrat deaths, the researchers were unable to draw solid conclusions about which pathogens or contaminants may be contributing to declining muskrat populations. However, the findings, recently published in Frontiers in Veterinary Science, were the first holistic review of muskrat mortality ever compiled.

The study provides a baseline for understanding the potential role of pathogens, contaminants, parasites and diseases in the declines of muskrat populations across North America, noted lead researcher Laken Ganoe, who conducted the work as part of her master’s degree thesis in wildlife and fisheries science.

“These data highlight critical knowledge gaps about muskrat health investigations and the circumstances surrounding and contributing to their decline that warrant future research efforts,” she said. “There is still much that we do not understand about why muskrats are disappearing, and to protect them into the future we need to better understand not only disease dynamics, but how other factors such as ecosystem dynamics and climatic factors are playing a role as well.”

In earlier research, done in collaboration with the Pennsylvania Game Commission, Ganoe collected muskrat carcasses from Pennsylvania trappers and conducted necropsies to develop a snapshot of muskrat health and exposure in the state, which included tissue sample collection and screening for a wide variety of pathogens and contaminants. She also captured muskrats, surgically implanted them with radio transmitters and then tracked them using radio telemetry, to determine their movement patterns, home range size and survival.

The Pennsylvania Game Commission and the U.S. Geological Survey funded this research.

Red squirrel and great spotted woodpecker

This 2016 video says about itself:

The red squirrel is one of Britain’s most treasured native creatures, but it’s also one of its most endangered.

A project aims to provide red squirrels with a brand new home in the Isles of Scilly where there are currently no grey squirrels.

A group of red squirrels from the British Wildlife Centre in Surrey was transported to Cornwall and then flown by helicopter from RNAS Culdrose to Tresco Abbey Gardens in September 2013.

Red Squirrels in The Abbey Gardens on The Island of Tresco, Isles of Scilly – Video Produced by Paul Dinning – Wildlife in Cornwall

Today, again to the cemetery.

Close to the entrance, a male great spotted woodpecker climbs up a tree.

A magpie up another tree.

A great tit and a nuthatch call.

A jay on a lawn.

A male blackbird on top of a tombstone. A female blackbird on the forest floor.

Then, a red squirrel up a tree. I had seen a red squirrel on this cemetery only once before, and that was almost ten years ago.