Sirens

Sirens (not to be confused with the salamanders in the genus siren or sirenians) are a genus within the porphin family. These small cetaceans live near stormraft fleets and follow them as they drift around. The genus contains two species, Seiren Borealis, the northern siren, and Seiren Australis, the southern siren. Northern sirens live in the North Atlantic ocean gyre while southern sirens live in the South Atlantic ocean gyre. They first evolved from normal oceanic porphins 

Biology

Sirens are small for oceanic porphins, they measure at about four feet and four inches in length. They have a pitch black coloration to help them hide themselves from the light of the moon and stars. They hunt after dusk and before dawn.

Sirens are very vocal creatures, this is due to their size. Sirens are smaller and need to deal with a lot of larger predators, so they evolved better methods of communication. They have stronger phonic lips, the cetacean equivalent of vocal chords. This gives them access to a wider range of sounds. Similarly, their echolocation has grown much better and they recieve much better readings of their surroundings. An amplified sense of echolocation is improved upon further as Sirens are able to change the shape of their melon which can control the sound waves.

Their diet consists of raft-dwelling land vertebrates along with the occasional drifter or small fish. Sirens stick to raft-dwellers due to intense competition with other porphin species that forced them out of both diurnal hunting and a mostly piscivorous diet. Over the course of the siren's evolution from a regular porphin into a siren, their snout has grown slightly shorter.

Behavior

Sirens are highly intelligent and social creatures. They live in pods of about 15 females with the oldest, a matriarch, in charge. Calves learn how to mimic all the nearby animals as well as how to identify them before going off on their own. Males live in groups of 5 that travel with the pod, usually having 2-3 mates in the pods. Males aren't as violent like the dolphins of our time are, but they will get violent when it comes to protecting the pod from predators.

 Sirens hunt by having one Siren sticking its head out of the water while the rest of the pod circles around it underwater. The Siren scans its surroundings using echolocation, it makes out which raft dweller species are out that night. It mimics the call of a raft-dwelling animal, usually a distress signal saying to swim to another raft, mating calls, or cries of juveniles. The siren's prey jump into the water upon hearing the loud call, the rest of the pod drag their prey underwater. This doesn't always work as some individuals will be cautious about whether or not the trust the siren's song. Pods travel to multiple different rafts throughout the night to hunt, the daytime is spent traveling and socializing. Finding prey is never hard as there are lots of rafts to choose from and raft-dwelling animals have a fast reproduction rate.