Some people call a group of tadpoles a “knot,” while others call them a “cloud,” or a “school.” We’ve been contemplating this same question here at the Houston toad program, wondering what to call the army (hey, that works!) of Houston toad tadpoles that will emerge from all of the eggs we have released into the wild. To date, the Houston Zoo’s Houston toad program has produced and released around 144,500 of eggs for release into Austin and Bastrop Counties! With less than 300 wild Houston toads remaining in Texas, we hope that this huge release of eggs will help to bolster the wild population and keep this irreplaceable amphibian off the extinction list.
In my last post I mentioned a cool contraption that our partners at Texas State University devised to keep our toad eggs safe while they develop into tadpoles. These predator excluder devices (or simply, egg cages) are placed around the egg strands to keep a host of predators out; including aquatic invertebrates, fish, birds, and even other amphibians. So are these egg cages working? Are our egg strands surviving outside the safety of the zoo in wild ponds?
The answer is yes! Every strand that has been released has successfully hatched and thousands of Houston toad tadpoles are being observed at all of the release sites. Our tadpoles are of course not the only amphibian tadpoles in the ponds, so how do we know that the ones we are seeing are in fact Houston toads? The tadpoles of many species of amphibians actually look very different from one another in both size and coloration. The Houston toad tadpole is typically very dark colored (black in fact), and they prefer to stay in shallow areas near the bottom (unlike the somewhat similar looking Spadefoot toad tadpoles that swim up and down in the water column).
TSU researchers have observed very large Houston toad tadpoles hanging around the egg cages, which mean that they are surviving. This large knot (or cloud, or school, or army) of tadpoles is rivaling the numbers that were observed back in the 1960’s before the number of Houston toads started to precipitously decline.
We are now anxiously awaiting the emergence of thousands of tiny Houston toad metamorphs from the water (surely, this should be called an “army!”) This will be the last time we see our toad babies before they disappear into the surrounding woodlands, and with any luck many of them will return to the ponds to breed early next spring. Everyone wish this army of tiny toads the best of luck – they are the future of their species!