How do newts survive high temps in the wild?

[stefanie]

take eastern newts for example. they can obviously survive the 90* summers we sometimes have in NYC. i've seen them in parks near my house, very healthy looking, even when it gets really hot out. but in captivity, they start showing signs of stress if the temperature approaches 75 (at least, mine always have).

i understand that outside, they have more shaded hiding areas and bigger (and probably cooler) ponds, but when it gets really hot here, it can be 85* in the shade or the water. yet the wild newts seem perfectly fine.

 

[jesper]

Don't they leave the water when too warm?
Normally the ground temperature is a lot lower than the air temp especially if you measure under leafes and moss and stuff. I suppose it gets even cooler if they start digging. In your tank everything is pretty much the same temp but in nature they can always find <75F spots.

 

[kaysie]

The rule of thumb is - The lower you go, the cooler it gets. This is how ambystomids beat the heat. Captive animals cant burrow too much, so you can either air condition them, move them to someplace cold (like the basement), or find a way to cool the tank. I have a modified cooler pump used to circulate ice water through a pad (like used when having knee surgery) and put that under the tank. However, it's costly and time consuming (always refilling with ice).

 

[jennifer]

This is something I have wondered too. Eastern newts have been found in the wild alive and well in shallow water over 80F. They don't leave the water and don't die.

I have two possible ideas. First, keeping a newt in captivity puts multiple stresses on it. Heat stress is one of them. Add heat stress to other stresses in the captive environment and you end up with a sick or dead newt. Second, in the wild, the high temperature may only happen for a few hours, and the animal may be able to find cooler places at night, while in captivity a hot house is likely to be hot day and night.

 

[edward]

Hi Everyone,
Here is another thought on the process. In the wild the size of the system may have a significant bearing on the rate of temperature increase. These pools and ponds are generally very large systems that take quite awhile to warm up to those higher temperatures. These slow acclimations (as compared to captive systems) would allow some leeway in the thermal tolerance of the animals. (There are some studies that bear this out. The maximal thermal tolerance of a caudate is to some extent dependent on the average temperature at which it was kept before the temperature increased.) Also in most of the aquatic systems, if the pool or pond is deep enough there may be a thermocline that the newts can use to regulate their temperature.
Most captive situations are either exposed to sudden dramatic temperature increases (like when the AC fails or is forgot to be turned back on) or is subject to wide swings in the temperature. Neither of these situations appears to be for the benefit of the amphibian. Some anurans are very sensitive to thermal increases. Some of the Phyllobates in the wild are found where it averages 80F yet Phyllobates maintained at 72-74 F in captivity show thermal stress and die if subjected to 80F.

Sorry for the rambling but its a little hard to concentrate at the moment.
Ed

 

[shawn]

personally i think they survive the wild by a form of evolution like the eastern newts that are out at a private pond on a horse ranch they dont have any shade and the water is just a shollow pond maybe 2 feet deep at max and they are doing just fine there in hot temps, they probably just adapt to their ecosystems just like if you purchase a newt that has been born and raised in a tank thats ~70F its gonna thrive at that temp because its what its used to but take a eastern newt thats used to living in 80F and he will probably continue to thrive at that temp. at least all the newts in the pond are and the pond is over loaded specially around the edges theres eastern red spotteds popping up all over the place i think at 1 given time i counted 42 within a 3 foot square area just hangin out about a foot off the edge of the pond doin there typical "zen" floating position. the next time im out that way i'll have to grab some pictures of em

Wolfie

 

[brian]

I always suspected that it had to do with where the population was coming from since I've seen Tarichas swimming and walking around when it's pretty warm. If there's any Taricha still captured it must be coming from pretty far north.