Hot or cold, venomous vipers still quick to strike
Cold weather makes rattlesnakes more vulnerable -- but not much

Date:
July 23, 2020
Source:
University of California - Riverside
Summary:
Most reptiles move slower when temperatures drop, but venomous
rattlesnakes appear to be an exception. The cold affects them,
but not as much as scientists expected.



FULL STORY ==========================================================================
Most reptiles move slower when temperatures drop, but venomous
rattlesnakes appear to be an exception. The cold affects them, but not
as much as scientists expected.


========================================================================== "Many reptiles and other animals that rely on external sources of heat
have muscles that don't contract as well when temperature drops. We
wanted to know if that was the case with rattlesnakes," explained UC
Riverside biologist Tim Higham.

To answer their question, Higham and a team from San Diego State
University examined the speed at which rattlers struck out at perceived
threats in temperature-controlled containers. The team's work is detailed
in a new paper published this week in the Journal of Experimental Biology.

The team investigated how quickly the snakes struck out to defend
themselves when faced with predators, as this speed can make the
difference between life and death in nature.

"Although humans often fear snakes, it is important to realize that snakes
are vulnerable to predation by animals such as birds, mammals, and other snakes," Higham said. "Defensive strikes are important for protecting
them against predation." When placed in the experimental containers,
the research team found that rattlers continued to strike quickly at a
balloon filled with warm water that played the role of an intruder.



==========================================================================
"By far, the hardest part of the study was working with snakes in the 35
C treatment," said San Diego State University doctoral student Malachi Whitford, first author of the new study. "The snakes were extremely fast, making them very difficult to corral." The strike speed was affected when
the temperature dropped, but not as much as the team thought it would be.

"We expected their strike to be about half as fast for every 10-degree
drop in temperature, but they're still able to uncoil and strike fairly rapidly, even at our lowest test temperatures," said SDSU ecologist and research team member Rulon Clark.

At most, the snakes were about 25 percent slower at the lowest
temperature. The finding means that pit vipers, the type of rattlesnake studied, are slightly more vulnerable to real or perceived threats in
colder temperatures but not by a lot.

This might help explain how rattlesnakes can thrive even in cooler
climates like southern Canada. It also suggests that the snakes are
using a mechanism other than just muscles in order to strike, as muscle movement becomes more difficult in the cold.

Kangaroos use tendons like elastic bands to bounce and hop without
using much energy, the way that humans use a bow and arrow. The findings suggest that snakes may also be storing elastic energy somehow.

"Striking in any way is important to do quickly," Higham said. "As global temperatures increase, it's possible that snakes will become even more effective predators."

========================================================================== Story Source: Materials provided by
University_of_California_-_Riverside. Note: Content may be edited for
style and length.


========================================================================== Journal Reference:
1. Malachi D. Whitford, Grace A. Freymiller, Timothy E. Higham,
Rulon W.

Clark. The effects of temperature on the defensive strikes of
rattlesnakes. The Journal of Experimental Biology, 2020; 223 (14):
jeb223859 DOI: 10.1242/jeb.223859 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/07/200723143700.htm

--- up 1 week, 1 day, 1 hour, 55 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1337:3/111)