So for December I’ve chosen the sperm whale, Physeter catodon as my skull of the month. This is because of my visit to the NHM large mammal storage collection where I saw a few of these skulls up close. They are HUGE! It’s really hard to gauge the size of a whale when you’ve only seen it on TV but in person the skull along was easily one and a half times the height of me.
I suppose the skull has to be large in order to house the largest brain on the planet. It’s head is up to a third of the whales body length and a male can grow to be over 60 ft (18m) making it the largest of the toothed whales. I can’t really explain how it feels to be stood next to a giant like this apart from incredible.
The skull of a sperm whale is very interesting anatomically. It has a flattened frontal bone which creates a bowl like shape above the maxilla where the spermaceti organ sites. This is a spongy tissue and along with another fatty tissue called the melon, which lies beneath it, is thought to assist with the transmission and receiving of sound.
One amazing thing of the skull of the sperm whale is that it doesn’t fully fuse. This can be contrasted with an adult human skull which will fuse completely by the mid-twenties. The lack of fusion in this whale is a result of diving to deep depths in the sea in order to feed and allows for the cranium to compress and the pressure increases. It’s slightly odd because when you’ve been used to looking at fully fused human skulls the sperm whales skull almost looks broken or cracked!
As already mention the sperm whale is the largest toothed mammal. They can have up to 26 pairs of conical teeth which are visible in the lower jaw but do not erupt in the upper jaw. Whales teeth are useful for research as the age of a whale can be determined by counting the growth lines which are present, just like I discussed for humans.
The sperm whale is an incredible creature and I aim to expand my knowledge on this animal this month. I’m going to search journal articles and various sources of information and will share what I find!
More recently there has been a discovery in Chile of multiple mass strandings resulting in the exacerbation of over 40 fossil marine mammals. Find out more here.