# Cannibal frogs? **URL:** \ **Category:** Factual Questions\ **Created:** [May 10, 2012, 12:03pm UTC](https://boards.straightdope.com/t/cannibal-frogs/621490 "2012-05-10T12:03:11Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![iiandyiiii](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/iiandyiiii/32/7924_2.png) [@iiandyiiii](https://boards.straightdope.com/u/iiandyiiii)\ **Post date:** [May 10, 2012, 12:03pm UTC](https://boards.straightdope.com/t/cannibal-frogs/621490/1 "2012-05-10T12:03:11Z")
In the sci-fi book “The Legacy of Heorot” by Niven and company, a reference is made to a species of frog that survives largely by eating the tadpoles of the same species (and only a small number reach adulthood). Does such a frog exist? If so, what species is it? ---
**Author:** ![penultima\_thule](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/penultima_thule/32/3833_2.png) [@penultima\_thule](https://boards.straightdope.com/u/penultima_thule)\ **Post date:** [May 10, 2012, 12:19pm UTC](https://boards.straightdope.com/t/cannibal-frogs/621490/2 "2012-05-10T12:19:11Z")
Would have thought that applied to a lot, if not all frog species. It’s a frog eat frog world. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [May 10, 2012, 12:33pm UTC](https://boards.straightdope.com/t/cannibal-frogs/621490/3 "2012-05-10T12:33:50Z")
It’s not inconcievable that a species could exist where the adults subsist _entirely_ on young of their own species - not sure if there is such a species, but it could be an effective strategy - the offspring in such a case would just be a delegated means of gathering food - as long as the reproductive rate is sufficient, and the young are sufficiently voracious and fast-growing, it’s sustainable. ---
**Author:** ![hogarth](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hogarth/32/1773_2.png) [@hogarth](https://boards.straightdope.com/u/hogarth)\ **Post date:** [May 10, 2012, 3:18pm UTC](https://boards.straightdope.com/t/cannibal-frogs/621490/4 "2012-05-10T15:18:19Z")
The idea is that the immature version eats one resource and the mature version eats the immature version. Here’s a mathematical paper on the subject: > **[017.pdf](https://epub.ub.uni-muenchen.de/5063/1/017.pdf)** ---
**Author:** ![Sailboat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sailboat/32/461_2.png) [@Sailboat](https://boards.straightdope.com/u/Sailboat)\ **Post date:** [May 10, 2012, 3:38pm UTC](https://boards.straightdope.com/t/cannibal-frogs/621490/5 "2012-05-10T15:38:42Z")
Well, _dendrobates vanzolinii_ has [an interesting solution](http://dendroworld.co.uk/BDGarchive/d_vanzolinii.html). ---
**Author:** ![ftg](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ftg/32/2801_2.png) [@ftg](https://boards.straightdope.com/u/ftg)\ **Post date:** [May 10, 2012, 3:48pm UTC](https://boards.straightdope.com/t/cannibal-frogs/621490/6 "2012-05-10T15:48:36Z")
Saw a PBS nature documentary about this years ago. Desert SW US. Small pools develop during the rainy season. The toads buried deep in the mud come up, do their thing and tadpoles ensue. Fairy shrimp are the primary food source initially. Most of the tadpoles are small, but a few are much larger (same species though). The larger ones start eating the smaller ones when the shrimp run out. Then the largest of the large eat the not quite so large, etc. A few make it to when the pool starts drying out, they mature and dig deep down into the mud. This might be the toads in question: [The Body Changers | Tadpole Tales | Nature | PBS](http://www.pbs.org/wnet/nature/episodes/the-body-changers/tadpole-tales/2925/) ---
**Author:** ![River\_Hippie](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/river_hippie/32/26_2.png) [@River\_Hippie](https://boards.straightdope.com/u/River_Hippie)\ **Post date:** [May 10, 2012, 8:17pm UTC](https://boards.straightdope.com/t/cannibal-frogs/621490/7 "2012-05-10T20:17:33Z")
We used to hunt bullfrogs and clean them for thier legs which we fried and ate. I always cut thier stomachs open to see what they had eaten. I don’t remember finding another frog but it would not surprise me in the least. I believe they will eat anything they can overpower and cram down thier throat. Things I did find: Bluegills Redwing blackbirds, young but past the chick stage. Snakes Small turtles Mice (might have been voles or shrews) ---
**Author:** ![hogarth](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hogarth/32/1773_2.png) [@hogarth](https://boards.straightdope.com/u/hogarth)\ **Post date:** [May 10, 2012, 8:45pm UTC](https://boards.straightdope.com/t/cannibal-frogs/621490/8 "2012-05-10T20:45:07Z")
> [@ftg](#): > > Saw a PBS nature documentary about this years ago. Desert SW US. Small pools develop during the rainy season. The toads buried deep in the mud come up, do their thing and tadpoles ensue. Fairy shrimp are the primary food source initially. Most of the tadpoles are small, but a few are much larger (same species though). The larger ones start eating the smaller ones when the shrimp run out. Then the largest of the large eat the not quite so large, etc. A few make it to when the pool starts drying out, they mature and dig deep down into the mud. > > This might be the toads in question: [The Body Changers | Tadpole Tales | Nature | PBS](http://www.pbs.org/wnet/nature/episodes/the-body-changers/tadpole-tales/2925/) Neat! It’s slightly different from the case mentioned in the Niven book, which states that the frog + tadpole population is at an equilibrium, not a boom and bust cycle.