This fish out of water cools down fast

http://www.eurekalert.org/pub_releases/2015-10/uog-tfo102115.php

Public Release: 21-Oct-2015
This fish out of water cools down fast: Study
University of Guelph

On hot, humid days, you might jump into water to cool down, but for the tiny mangrove rivulus fish, cooling down means jumping out of water, according to a new study from the University of Guelph.

In the study published today in the journal Biology Letters, the researchers describe how these fish air-chill themselves on solid ground in order to drop their body temperatures. The researchers also found that fish exposed to higher temperatures for a week tolerated warmer water better.

The fish jump out of the water to escape rising temperatures, said integrative biology professor Pat Wright, senior author of the study.

"If the fish are prevented from jumping out of the water, they would die," she said.

"The water evaporates off the fish and they cool down their body temperatures slightly. It only takes about a couple seconds for the fish to start to cool down."

The rivulus fish live in waters from Florida to Brazil, where water temperatures can reach 38 C (100.4 F). (Normal human body temperature is 37 C.)

•••••

Wright said the fish wriggle to a chosen spot once on land and even find their way by barriers.

"These fish will also jump out because of conflict with other rivulus fish or looking for food, but the primary reason is to cool their bodies down," said Wright.

"As climate change continues, and temperatures in their habitats continue to increase, we could potentially see them jumping more."

•••••