Happy International Day of the Seal!
We all know that seals are very, very cool, so let’s celebrate with these sealy good facts (promise - they’re better than my puns!)
The biggest seal in the world!
Say hello to the southern elephant seal (Mirounga leonina)! And in particular, male southern elephant seals.
Southern elephant seals are what is known as sexually dimorphic, essentially meaning that there are some very distinguishable features between males and females. In the case of our elephant seal, that feature is size.
Adult female southern elephant seals typically reach lengths up to three metres and weigh somewhere between 400 kg and 900 kg. Males, on the other hand, grow up to almost six metres in length and weigh up to 4,000 kg!
Not only are southern elephant seals the largest seals alive today, but they are also the largest seal to have ever lived and the largest ever marine mammal that isn’t a cetacean!
Credit: User:Air55/Wikimedia (CC BY-SA 4.0)
The smallest seal in the world
Named after the patterning of dark spots with grey rings, the ringed seal (Pusa hispida) averages just 1.5 metres in length and weighs between 50 kg and 70 kg.
Compared to the southern elephant seal, that’s tiny!
Credit: NOAA Seal Survey (Public Domain)
The seal with a mystery
In southern Siberia lays Lake Baikal, home to the Baikal seal. Thousands of kilometres from the ocean and without an access channel connecting the two, how the seals got to the lake is somewhat of a mystery.
Scientists think that an access must have existed millions of years ago but has since been lost. Genetic analysis suggests the seals have been living at the lake for around two million years.
Credit: Nina Zhavoronkova/Wikimedia (CC BY-SA 4.0)
Rarest seal in the world
There are two contenders here - Mediterranean monk seals and Saimaa ringed seals.
There are just 700 Mediterranean monk seals (Monachus monachus) left in the world. They are distributed among a few sub-populations, the largest in Greece (~300 individuals), then Cabo Blanco (~270 individuals). Turkey is thought to hold around 100 individuals.
But if you consider subspecies, the Saimaa ringed seal (Pusa hispida saimensis) - a subspecies of ringed seal - is much rarer. The 400 Saimaa’s live exclusively in Finland’s Lake Saimaa.
A Mediterranean monk seal. Credit: Wildlife Wanderer/Flickr (CC BY-NC-ND 2.0)
A Saimaa ringed seal. Credit: Aki Mykkänen/Flickr (CC BY-NC 2.0)