Navigation Links
Snakes on the brain: Are primates hard-wired to see snakes?

Was the evolution of high-quality vision in our ancestors driven by the threat of snakes? Work by neuroscientists in Japan and Brazil is supporting the theory originally put forward by Lynne Isbell, professor of anthropology at the University of California, Davis.

In a paper published Oct. 28 in the journal Proceedings of the National Academy of Sciences, Isbell; Hisao Nishijo and Quan Van Le at Toyama University, Japan; and Rafael Maior and Carlos Tomaz at the University of Brasilia, Brazil; and colleagues show that there are specific nerve cells in the brains of rhesus macaque monkeys that respond to images of snakes.

The snake-sensitive neurons were more numerous, and responded more strongly and rapidly, than other nerve cells that fired in response to images of macaque faces or hands, or to geometric shapes. Isbell said she was surprised that more neurons responded to snakes than to faces, given that primates are highly social animals.

"We're finding results consistent with the idea that snakes have exerted strong selective pressure on primates," Isbell said.

Isbell originally published her hypothesis in 2006, following up with a book, "The Fruit, the Tree and the Serpent" (Harvard University Press, 2009) in which she argued that our primate ancestors evolved good, close-range vision primarily to spot and avoid dangerous snakes.

Modern mammals and snakes big enough to eat them evolved at about the same time, 100 million years ago. Venomous snakes are thought to have appeared about 60 million years ago "ambush predators" that have shared the trees and grasslands with primates.

Nishijo's laboratory studies the neural mechanisms responsible for emotion and fear in rhesus macaque monkeys, especially instinctive responses that occur without learning or memory. Previous researchers have used snakes to provoke fear in monkeys, he noted. When Nishijo heard of Isbell's theory, he thought it might explain why monkeys are so afraid of snakes.

"The results show that the brain has special neural circuits to detect snakes, and this suggests that the neural circuits to detect snakes have been genetically encoded," Nishijo said.

The monkeys tested in the experiment were reared in a walled colony and neither had previously encountered a real snake.

"I don't see another way to explain the sensitivity of these neurons to snakes except through an evolutionary path," Isbell said.

Isbell said she's pleased to be able to collaborate with neuroscientists.

"I don't do neuroscience and they don't do evolution, but we can put our brains together and I think it brings a wider perspective to neuroscience and new insights for evolution," she said.


Contact: Andy Fell
University of California - Davis

Related biology news :

1. New paper examines poison resistance in snakes around the world
2. Robosquirrels versus rattlesnakes
3. Big-mouthed babies drove the evolution of giant island snakes
4. Scientists discover new type of virus responsible for a devastating disease in snakes
5. Snakes minus birds equals more spiders for Guam
6. Global warming beneficial to ratsnakes
7. Scientists discover reasons behind snakes shrinking heads
8. Snakes devour more mosquito-eating birds as climate change heats forests
9. Protecting your brain: Use it or lose it
10. Good news for nanomedicine: Quantum dots appear safe in pioneering study on primates
11. Manipulation of a specific neural circuit buried in complicated brain networks in primates
Post Your Comments:
(Date:10/29/2015)... Oct. 29, 2015 Daon, a global leader ... has released a new version of its IdentityX ... North America have already installed IdentityX ... includes a FIDO UAF certified server component ... to activate FIDO features. These customers include some of ...
(Date:10/27/2015)... 27, 2015 In the present market scenario, ... for various industry verticals such as banking, healthcare, defense, ... growing demand for secure & simplified access control and ... as hacking of bank accounts, misuse of users, , ... as PC,s, laptops, and smartphones are expected to provide ...
(Date:10/26/2015)... NEWARK, Calif. , Oct. 26, 2015  Delta ... convenient biometric authentication to mobile and PC devices, announced ... Fujitsu,s smartphone, the arrows NX F-02H launched by NTT ... arrows NX F-02H is the second smartphone to include ... this technology in ARROWS NX F-04G in May 2015, ...
Breaking Biology News(10 mins):
(Date:11/27/2015)... 2015 --> ... companion diagnostics is one of the major ... pharmaceutical companies and diagnostic manufacturers working together ... . --> ... global cancer biomarkers market spread across 89 ...
(Date:11/25/2015)... 26, 2015 --> ... 2016 - 2020 report analyzes that automating biobanking ... quality in long-term samples, minimizing manual errors, improving ... minimizes manual errors such as mislabeling or inaccurate ... it plays a vital role in blood fractionation, ...
(Date:11/25/2015)... Studies reveal the differences in ... pave the way for more effective treatment for one of ...   --> --> Gum ... in cats, yet relatively little was understood about the bacteria ... been conducted by researchers from the WALTHAM Centre for Pet ...
(Date:11/25/2015)... QUEBEC CITY , Nov. 25, 2015 /PRNewswire/ ... "Company"), affirms that its business and prospects remain ... , Zoptrex™ (zoptarelin doxorubicin) recently received DSMB ... program to completion following review of the final ... met Phase 2 Primary Endpoint in men with ...
Breaking Biology Technology: