Can’t we all just get along – like India’s cats and dogs?

Date: February 16, 2017

Source: Wildlife Conservation Society

A new WCS study in India shows that three carnivores -- tigers, leopards, and dholes (Asian wild dog) -- seemingly in direct competition with one other, are living side by side with surprisingly little conflict. Usually, big cats and wild canids live in different locations to avoid each other.

Yet in four relatively small reserves in India's wildlife-rich Western Ghats region, WCS researchers have found that they are co-existing, despite competing for much of the same prey, including sambar deer, chital, and pigs.

Using dozens of non-invasive camera traps for sampling entire populations, rather than track a handful of individuals, the research team recorded some 2,500 images of the three predators in action.

The authors found that in reserves with an abundance of prey, dholes, which are active during the day, did not come in much contact with the more nocturnal tigers and leopards. But in Bhadra Reserve where prey was scarcer, their active times overlapped, yet dholes still managed to avoid the big cats. In Nagarahole, a park teeming with all three carnivores and their prey, leopards actively to avoid tigers.

Overall, the authors say that these carnivores have developed smart adaptations to coexist, even while they exploit the same prey base. However, these mechanisms vary depending on density of prey resources and possibly other habitat features.

Said Ullas Karanth, WCS Director for Science in Asia and lead author of the study: "Tigers, leopards, and dholes are doing a delicate dance in these protected areas, and all are managing to survive. We were surprised to see how each species has remarkably different adaptations to prey on different prey sizes, use different habitat types and be active at different times. Because of small and isolated nature of these high prey densities in these reserves, such adaptions are helpful for conservationists trying to save all three."

Read more

Whales use nested Russian-doll structure to protect nerve tissue during lunge dives

Date: February 16, 2017

Source: University of British Columbia

Fin whales use two neatly packed levels of nested folds to protect the nerves along the floor of their mouth during lunge feeding, according to new research from University of British Columbia zoologists.

Large whales balloon an immense pocket between their body wall and overlying blubber to store captured prey during feeding dives -- extending nerves along their mouth and tongue to more than double their length.

"But when they shorten again these nerves have to fold so tightly that they develop bending stretches, which could damage the nerve," says UBC zoologist Margo Lillie, author of the paper in Current Biology. "It surprised me that just folding them up created a problem."

The solution: the nerves use a Russian doll-like structure to nest folds.

"The first level of waviness allows the nerve to extend when feeding. Then the nerve structure is folded at a second level of waviness at a smaller length scale -- that creates enough slack in the shortened nerve tissue to allow it to go around each fold without being damaged."

The whale nerves are so large that Lillie and UBC colleagues Wayne Vogl, Kelsey Gil, John Gosline and Robert Shadwick were able to use microCT to visualize the nerve's 3D structure.

Read further 

'Tully monster' mystery is far from solved, group argues

Date: February 20, 2017

Source: University of Pennsylvania

Last year, headlines in The New York Times, The Atlantic, Scientific American and other outlets declared that a decades-old paleontological mystery had been solved. The "Tully monster," an ancient animal that had long defied classification, was in fact a vertebrate, two groups of scientists claimed. Specifically, it seemed to be a type of fish called a lamprey.

The problem with this resolution? According to a group of paleobiologists led by the University of Pennsylvania's Lauren Sallan, it's plain wrong.

"This animal doesn't fit easy classification because it's so weird," said Sallan, an assistant professor in Penn's School of Arts & Sciences' Department of Earth and Environmental Science. "It has these eyes that are on stalks and it has this pincer at the end of a long proboscis and there's even disagreement about which way is up. But the last thing that the Tully monster could be is a fish."

In a new report in the journal Palaeontology, Sallan and colleagues argue that the two papers that seemingly settled the Tully monster debate are flawed, failing to definitively classify it as a vertebrate. The mystery of the Tully monster, known to scientists as Tullimonstrum gregarium, remains.

"It's important to incorporate all lines of evidence when considering enigmatic fossils: anatomical, preservational and comparative," said Sam Giles, a junior research fellow at the University of Oxford and coauthor of the study. "Applying that standard to the Tully monster argues strongly against a vertebrate identity."

Read more