The Tragic Story of Tillikum

 

Dorsal Fins

The dorsal fin of the orca is the fin that is pointing upwards on the midline of their backs, which aids them to swim through water more efficiently. Anatomy of the dorsal fin varies between male and female killer whale - with the male's being much taller than the female's. However, over the years, scientists have seen dorsal fins of captive whales varying from orcas that are not captive.

As killer whales travel on average 100 miles per day, their dorsal fins are much more upright due to the water pressure keeping their dorsal fin tissue healthy and straight. However, since captive killer whales do not have the space to travel for these vast distances, the tissues within the dorsal fins are weak - causing the fin to flop over. This is called "dorsal fin collapse" and although there are a few cases of dorsal fin collapse in the wild, it is seen the most in orcas that are captive. 

(Dorsal fin collapse seen in SeaWorld's late orca, Tillikum.)

Migration and Habitat

 The killer whale can be found in several regions of the world such as Arctic and Antarctic regions and even in tropical seas. This is because they are known in biology as 'regulators' meaning they use their metabolism to control their internal environment regardless of their external environment, which is why they can be found in a variety of drastically different environments.

A handful of arteries of the flippers, flukes and dorsal fin are local to veins. Therefore, some heat from blood moving through the arteries is transferred to venous blood rather than the external environment. This is called counter current heat exchange. Also when a whale dives, circulation at the skin decreases which moves blood to the insulated body core. In cases where orcas must dissipate body heat, circulation will increase near the surface of the flippers, dorsal fin and flukes before escaping into the external environment.

This is extremely advantageous for orcas, as they are known to swim up to 100 miles per day. Therefore, they are not restricted to where they can swim.

Teeth

 Orcas have 10 to14 large, cone-shaped teeth on either side of their jaw that are approximately four inches long. This means that the total amount of teeth within their mouths - upper jaw and lower jaw - is 48 to 52 teeth. By the time they are 11 to 12 weeks of age, killer whales will have a full set of teeth. Their teeth are conical and sharp in order to aid the mammals in ripping their food apart into chunks that are much easier to swallow.

(Up close of an orca's mouth and teeth)

Orca Pod Hunting

Every killer whale that resides within the wild belongs to a pod, which consists of every family member that they are related to - from grandmother to cousins - and will spend their entire life around their pod. Since the pod will always stick together, they will even hunt prey together using hunting techniques that are unique to their pod. This means that excellent teamwork while hunting is absolutely essential to the pod as it maximises the success of the hunt, meaning the pod will be able to thrive.

(A pod of Antarctic killer whales working together by breaking sections of ice that the seal is laying on so they can capture the seal)

J-Pod Orca Calf

 Like any species, welcoming a new member to the family is a massive, heart-warming event. The one out of three southern resident pods that are endangered, the J-Pod, welcome a new calf to their family in 2019. This means they are one step closer to no longer being endangered.

(Image of the new J-Pod calf)

The Apex Predator

Being an apex predator, killer whales are at the top of the food chain. The orca's diet is not limited to just fish and squid, like many other toothed whales' diets are, they will also target birds, seal lions, penguins and other whales; however killer whales are also known to target great white sharks. This makes them the only known predator to great white sharks.

 (An orca waiting to fest on a group of penguins in the Antarctic.)