Flukes Up - The Hand of God
Whalers termed the upturned flukes the hand of god. The flukes of an angry whale are a formidable weapon and more than capable of splintering a whale boat. Seeing the hand of god from a fragile whaleboat would certainly bring home thoughts of mortality and nature's life or death lottery in this inherently dangerous profession.
A Quick Bite - Cookie Cutter Sharks
A cheeky cookie cutter shark has made a daring dash and taken a crescent shaped chunk from the right lobe of this whale's fluke.
Sperm whales continually slough skeins of skin - see the the lighter grey area in the centre of the fluke.
Tailslapping - Lobtailing
The repeated percussion of a lobtailing whale as it slaps its flukes on the ocean's surface produces impressive acoustics. Even more impressive is that this high energy behaviour can continue seemingly without fatigue for 10 minutes or more.
We have also seen this behaviour regularly in humpback whales. It could be to dislodge parasites but also it seems to serve some social purpose. On the day this image was taken the whales were travelling in pods and forgone their foraging dives. We attributed this behavioural change to the presence of a pod of pseudorcas (false killer whales).
Scars Betray a Close Shave
Deep scarring on the dorsal hump is witness to what must have been a near fatal orca (killer whale) attack. Orcas are the only serious sperm whale predators and these scars are extensive and deep. The attack may have occurred when this whale was merely a calf. It exhibited no visible adverse effects during swimming and diving.
The small white crustacean is a whale louse. The louse is actually a skeleton shrimp from the Cyamidae family. On sperm whales, the species of parasitic cyamids present are different for male and female whales. There is scarring on the whale where two cyamids have been dislodged.
There is little respite from whale lice. I have seen calves with many lice attached within a few hours of birth.
The flukes in the lower image are also the result of an orca attack. Orcas will work in a pack to hold a whale down to try and drown it.
A Battle Scarred Head
Not all scars can be attributed to life or death battles. These rake marks are from sperm whale teeth. Whether they are from friendly interactions during marguerites (whales getting together) or internecine rivalry is impossible to tell.
Big Headed Blowers & Monkey Muzzles
Its scientific name Physeter macrocephalus means 'big headed blower.' The bluff head is filled with spermaceti oil (this waxy oil was originally mistaken for semen hence the misleading name of this species). The oil is a transmission media for the whale's echo location clicks. The head of a male may be one third of its 17 metre body length. They are easily recognisable by the distinct bump on the back of the head. Females are smaller at 12 metres.
The single blow hole is asymmetric on the left hand side of the head. The blow is distinctive - forward and to the left.
The right nostril is closed and terminates in an air sac called a 'museau du singe' or 'monkey muzzle.' The monkey muzzle is a valve like clapper system and it is thought the passage of air through these lips produces the acoustic clicks which are then amplified and reflected through the oil-filled spermaceti organ.
The spermaceti organ dominates the head giving it its double barrelled bulbous shape and represents 25-30% of the animals body. it was this highly prised and priced oil that motivated the sperm whale's human predators.
This unique physiology plays a key role in sperm whale behaviour, hunting and socialisation. The clicks vary in frequency and acoustic power and seem to be used for both echolocation and communication. Some clicks are audible for 60 km and the sound power can be up to 223 decibels.
Some Days You Should Stay In Bed
The whales are very comfortable in rough seas (at great risk of stating the obvious) but less approachable. The distinctive bulge at the back of the head of the closest whale shows it is a male. The sea conditions on this day triumphed over enthusiasm. I should have stayed in bed.