Bottlenosed dolphins hunt baitfish, including this ballyhoo, for food.
These fish must be swallowed head-first to avoid potiential injury or
death from choking.
She bit off the head of the fish, before throwing the body in the air, for her calf to catch. We could not help but make the comparison of a mother cutting the crust off a sandwich, before serving it to her child. But it is more than that; she was keeping her calf safe.
For the significance of this simple act, we need to first examine the basic anatomy of a fish. Fish use gills to acquire oxygen from the water. These gills are located just at the base of the head. When a fish breathes, it draws in a mouthful of water and pulls the sides of its throat together, forcing the water through the gill openings, which expand away from the body.
To protect her calf from choking, Odyssey carefully removes the head
of the fish.
Dolphins do not chew their food. It is imperative, therefore, for a dolphin to swallow their prey, head first.
If a fish were eaten tail first, it might expand its gills while passing through the throat of the dolphin, and become wedged. In all the necropsies I performed, I once found one dolphin with a fish caught in it’s throat. The fish was swallowed tail first, and the result was deadly.
Odyssey subdues and tosses baitfish in the air, then tosses them to her
calf prepared to safely eat.
Back to Odyssey and her calf. She was biting the heads off the fish, so her calf would not catch the fish backwards and choke to death. She threw the fish body high in the air, and her calf made repeated attempts to make the catch. More likely motivated by the game than the food, the small dolphin was still nursing and probably not too hungry. Over the next few months, as this calf grows, Odyssey will insist it hunt down its own food. The catching strategies learned now, will be all the more important in the future.
Odyssey’s calf catches fish that she has prepared by skillfully removing
the head and gills.
But even the best strategies and the most prepared youngster will not grow to be an adult unless there continues to be the abundance and variety of fish to eat.