Kangaroo rats against rattlesnakes


This 26 March 2019 video says about itself:

Kangaroo rat defensive kicking of rattlesnake while jumping

High speed recording of a desert kangaroo rat (Dipodomys deserti) defensively kicking away a sidewinder rattlesnake (Crotalus cerastes) in mid-air. The animals are free-ranging in their natural desert habitat at night, and filmed with high speed cameras using near-IR lights invisible to both species. The video is recorded at 500 frames per second, and playback is slowed down about 30 times. This clip shows the ability of kangaroo rats to avoid venom injection even when bitten by using a forceful mid-air kick to dislodge the snake and push it away. Scientific details of this study are published in Freymiller et al (2019, doi 10.1093/biolinnean/blz027). Find more information and additional bonus videos here.

See also here.

Advertisements

Swedish squirrel, birds eat nuts


This 13 March 2019 video shows a Swedish red squirrel and various birds eat nuts.

Featuring spotted nutcracker, jay and nuthatch.

Costa Rican singing mice, new study


This 2013 video says about itself:

Singing Mouse Serenades The Sky. Really.

Move over Celine Dion. Alston’s singing mouse (Scotinomys teguina) emits sopranino trills to mark its boundaries deep in mountain cloud forests. [The little vocalist even takes a bow.]

From the NYU Langone Health / NYU School of Medicine in the USA:

Study of singing mice suggests how mammalian brain achieves conversation

Research may lead to future solutions to speech problems

February 28, 2019

By studying the songs of mice from the cloud forests of Costa Rica, researchers have discovered a brain circuit that may enable the high-speed back and forth of conversation.

Males of the study species, Alston’s singing mouse (Scotinomys teguina), produce songs with nearly a hundred audible notes. They challenge competitors by singing in turns, alternating like talking humans, say the study authors. In contrast, standard laboratory mice produce ultrasonic sounds without evident exchanges.

Thus, the new study, led by researchers at NYU School of Medicine, launches a new field by employing a novel mammalian model to examine brain mechanisms behind the sub-second precision of vocal turn-taking.

“Our work directly demonstrates that a brain region called the motor cortex is needed for both these mice and for humans to vocally interact,” says senior study author Michael Long, PhD, an associate professor of neuroscience at NYU School of Medicine.

“We need to understand how our brains generate verbal replies instantly using nearly a hundred muscles if we are to design new treatments for the many Americans for whom this process has failed, often because of diseases such as autism or traumatic events, like stroke,” says Long.

Published online as the cover story of Science on March 1, the study found that, along with brain areas that tell muscles to create notes, separate circuits in the motor cortex enable the fast starts and stops that form a conversation between vocal partners.

“By segregating sound production and control circuits, evolution has equipped the brains of singing mice with the tight vocal control also seen in cricket exchanges, bird duets, and possibly, human discussion,” adds study co-first author Arkarup Banerjee, PhD, a post-doctoral scholar in Long’s lab.

Despite the ubiquity of vocal exchanges in the natural world, he says, there are no suitable mammalian models in neuroscience for their study. Before the new report, the leading model for studying this back-and-forth was the marmoset, a primate whose conversational turns are considerably slower than human speech, and unlikely to result from the fast muscle response to sensory cues (e.g. motor cortical circuitry).

Social Songs Different

The research team found that S. teguina songs — series of notes that evolve predictably as the song goes on — changed in social situations as the mice had to “bend and break the songs” to converse. The tight connection between song patterns and readings taken by electromyography, which captures electrical signals as the brain generates muscle contractions, enabled the team to determine the relationships between brain centers and song musculature while two mice coordinated their responses.

In contrast to the findings of past studies, the researchers found that a functional “hotspot” located at the front of the motor cortex to one side — the orofacial motor cortex or OMC — regulated song timing.

To study the contributions of these specialized brain circuits to social singing, the team interfered with cortical regions in the mice using a number of techniques, including devices that cooled the OMC during songs. Long has helped to pioneer the cooling technique in the study of human brain circuits related to speech.

Called focal cooling, it is a safe way to slow the pace of vocalizations without changing the pitch, tone, or duration of individual notes, say the study authors. They argue that the observed, functional separation in the brain between sound generation and timing functions, this hierarchy, is what makes socially relevant exchanges possible.

Moving forward, the researchers are already using their mouse model to guide related exploration of speech circuits in human brains. By understanding the activity that helps to engage two brains in conversation, they can look for the processes that go awry when disease interferes with communication, potentially spurring the development of new treatments for many disorders.

Along with Long, study authors from the NYU Neuroscience Institute and Department of Otolaryngology at NYU School of Medicine were co-first authors Arkarup Banerjee and Daniel Okobi Jr, as well as Andrew Matheson. The work was done in collaboration with Steven Phelps, PhD, director of the Center for Brain, Behavior and Evolution at the University of Texas at Austin, whose lab pioneered the study of the singing mouse in the lab and field. Some of the authors are also members of the Center for Neural Science at New York University.

This research was supported by the New York Stem Cell Foundation, the Simons Foundation Society of Fellows, and the Simons Collaboration on the Global Brain.

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.”