Caudate prey prefferences

[benjamin]

It's almost common knowledge that many great mammilian predators, such as the great cats, wolves, and bears, always go for the weakest, smallest, and sickest looking animals when hunting. My caudates, however, seem to behave in the opposite way always going for the larger food item. My finger, for example, attracts more attention than a worm when it goes into their tanks; larger worms are more desired than smaller worms; worms are taken over woodlouse etc. Has any one else noticed behaviour like this, have there been any studies on it, and could going for larger fatter prey items be more beneficial for a caudate?

 

[william]

large carnivores go for the weaker specimens because they are easier to catch and are less likely to do damage. a larger and healthier worm won't have the ability to do much more damage to the caudate as a smaller weaker one could.

btw i know what you mean by caudates liking fingers better then worms, i have to feed my pachytriton with tweezers now since they always go for the finger and ignore the worm

 

[kari]

i think its to do with natural selection - the weaker ones may be easier to catch but also stand a good chance of transmitting disease and if they are weak/dying then are likely contain less nutrients! dunno its just my theory! My axolotl goes for the largest and strongest prey in the tank although not fingers yet!!!!

 

[mark]

I think this is missing the point somewhat. A newts feeding response is largely based on prey movement. The brain power to make complex decisions about the fitness of a prey item does not exist. "Can I fit it in my mouth?" is probably as good as it gets. The bigger the prey the easier it is to see, thus more likely to be chosen over smaller items. In captivity there seems to be some learned response to feeding time (with some species at least)which is why they sometimes go for fingers or tackle prey that is oversized. In the wild I suspect they are more cautious about prey size.

 

[michael]

I've noticed my Tylototriton kweichowensis tend to watch me when I feed. Some don't go after the food until I back away from the tank. They look up like they are trying to communicate with me. I don't know what they want to say.

 

[alan]

They are saying "I can't eat until that big hairy predator goes away"

 

[mark]

LOL

I think they might be saying:

"I didn't order that. I asked for the 8oz steak with chips."

 

[edward]

What typically happens is that the stimulus of the presence (vibrations from footfalls, sight etc)of the keeper combined with the offering of food acts as a positively reinforced learned response. This is different than the evaluation of a prey item for its nutritional content (which is documented to occur in at least Plethodon cinereus).

Ed

 

[mark]

Hey Ed, you can't drop a nugget of info in like that without a bit more explanation.

Do you mean that P.cinereus shows a preference for the more nutritional items, given the choice i.e. worm vs caterpillar or that it can evaluate the health of the item i.e healthy worm vs sick worm?

 

[edward]

Hi Mark,

P. cinereus has been shown not only discriminate over more calorically rich prey (termites vs ants or ants vs fruit flies)but the size of the territory and vigor by which it defends its territory also depends on the caloric content of the predominate prey items.
Ed