Thanks to Kai and Emily for their suggestions this week!

The greater siren [photo by Kevin Stohlgren, taken from this site]:



The anhinga [photo by Tim from Ithaca - Anhinga, CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=15526948]:



An anhinga swimming [photo by Wknight94, CC BY-SA 3.0 , via Wikimedia Commons]:



Show transcript:
Welcome to Strange Animals Podcast. I’m your host, Kate Shaw.
This week we’re going to learn about two animals, one suggested by Kai and the other suggested by Kai’s mom Emily. It’s so awesome to hear when families like to listen to the podcast together. This episode even includes a mystery animal I bet you’ve never heard of.
Let’s start with Kai’s suggestion, the greater siren. The greater siren is an amphibian, specifically a salamander, but it’s probably not the kind of salamander you’re thinking of. For one thing, it can grow over three feet long, or about a meter, which is pretty darn big for a salamander. It’s dark green or gray in color with tiny yellow or green speckles, and while it has short front legs, those are the only legs it has or needs. It also has external gills which it keeps throughout its life, unlike most salamanders who lose their external gills when they metamorphose into adults.
The greater siren lives primarily in Florida, but it’s also found in coastal wetlands throughout much of the southeastern United States. It’s mostly nocturnal and during the day it hides among water plants or under rocks, and will even burrow into the mud. At night it comes out to find food, which includes crayfish and other crustaceans, insects and spiders, little fish, other amphibians, snails, and even algae. It swallows its food whole, even snails and other mollusks. It poops out the shells and other undigestible pieces.
The grater siren’s body is long but thin, sort of like an eel, with a rounded tail that’s slightly flattened to help it swim. While it does spend its whole life in the water, it has small lungs that allow it to breathe air if it needs to. It can wriggle above ground for short distances if it needs to find a new pond or river, and sometimes it will sun itself on shore. In drought conditions when its water dries up, the greater siren will burrow into the mud and secrete mucus that mixes with dead skin cells to form a sort of cocoon. The cocoon covers everything but the siren’s mouth, so it can still breathe. Then it enters a state of torpor called aestivation, and it can stay in its mud cocoon for a long time, possibly as much as five years, and still be fine once the water returns. It does lose a lot of its body fat and its gills wither away, but it regenerates them quickly once it has water, and will gain weight quickly too once it has food.
In early spring, the female siren lays her eggs in shallow water. The male fertilizes them and takes care of them for the next two months, when they hatch into little bitty sirens that go off on their own right away.
The greater siren has tiny eyes and probably doesn’t see very well. It has a good sense of smell instead, and it can also sense movement and vibrations around it with its lateral line system. This is an organ found in many fish and a lot of larval amphibians, although the greater siren retains it throughout its life. It allows the animal to sense the movement of water in extremely fine detail. The greater siren can probably also sense electrical impulses, which is something that all animals generate when they use their muscles.
If there’s a greater siren, you may be thinking, there must be a lesser siren too. There is, and it’s very similar to the greater siren, just not as big. It only grows about two feet long at most, or 61 cm.
Kai mentioned that the greater siren looks a lot like the axolotl, a critically endangered salamander found only in Mexico. I checked to see if the two salamanders were closely related and was actually surprised t...