Friday, April 13, 2007

Sea cow appreciation

Sirens are creatures of Greek mythology described as being beautiful nymphs who would lure sailors to rocky cliffs with their bewitching singing, cause them to shipwreck and then devour their bodies. These seductive beings are generally depicted as young maidens of exquisite beauty. So why exactly would anyone associate them with sea cows? Sea-cows are part of the Order Sirenia, which includes dugongs and manatees. I really like Sirenians, they are many things to many people, but they are not hot. They are however very interesting, unique animals. Sirenians are the only marine mammals that are entirely herbivorous. Their diet consists almost entirely of sea grass, which is related to terrestrial flowering plants and is not a seaweed (which are algae, not plants). Sea grass is restricted to shallow marine habitats where there is enough light to enable photosynthesis and this is where you find modern Sirenians. The group shares a common ancestor with elephants and are the only group of herbivorous mammals to have completely adapted to an aquatic habitat. Although modern Sirenians are extremely intolerant of cold temperatures and restricted to warm seas, this was not always the case. There are a number of fossil representatives of the group from temperate regions. My favourite Sirenian is one of these cold-water adapted species called Stellar's sea cow (Hydrodamalis gigas). Stellar's sea cow was found around islands in Bering Strait and (as the species name suggests) was a giant measuring up to 7.9 metres and weighing around 3 tons. That's freaking huge - imagine a sea cow the size of a small whale. Unfortunately, the predictable reliability of human violence and ignorance coupled with the slow reproductive rate of Hydrodamalis gigas meant that they were hunted to extinction by 1768, 27 years after its discovery. Nice work. There goes my chance to see a sea cow as big as a Minke whale.

2 comments:

Roger said...

Sirenians are vegetarians.

∴ Sirenia = Cool.

They are, however, also coprophagous.

ChaZz said...

nice blog :)