Predators of penguins
In the Antarctic, killer whales and leopard seals regularly eat penguins. The predators usually patrol along the coast just outside the penguin colony, where large numbers of the aquatic birds come and go. I haven't watched killer whales preying on penguins, but I have seen many attacks by leopard seals on Adelie penguins--close relatives of the gentoos.
The leopard seal skins the penguin after catching one, tossing it violently too and fro while hanging onto a flap of skin, until the skin comes off.
For the much larger killer whales, skinning penguins is probably too delicate a task. For them, a penguin would be little more than a peanut is for us.
Penguins can probably turn much more tightly than a a seal or killer whale, so that is their only hope of escape--that, or jumping up onto the ice (or onto a boat).
When trying to catch penguins on land with a snowmobile (for scientific research), the penguins easily out turn the vehicle. You have to jump off the snowmobile with a net, and dash after them for the final capture.
By swimming fast under water, then turning upward, penguins can jump about two meters above the water at the edge of an ice floe, plopping down onto their feet on the ice. They need to do this because the chunks of floating ice have vertical edges, often several feet high. Floating sea ice can be about ten feet thick. If 1/10 of that floats above the surface, then the penguins have to be able to jump at least one foot high to get onto a typical block of ice.
So, having a penguin escape onto a small boat would be a perfectly normal kind of behavior. Once landing, and seeing the people, the penguin normally wouldn't be afraid, because they have no land predators (other than scavenging birds that take chicks). So over the eons, they have lost their fear of any large animals on land, because it serves no purpose.
However, penguins do have a sense of personal distance. They would normally be uncomfortable with a person being closer than about six feet--although the exact distance depends on the personality of the individual penguin.
What I found interesting about this video was that the penguin didn't seem to mind a number of people closer than six feet. I suspect he sensed that he was safer where he was on the boat. In the water, it would have been almost certain death.
Grabbing a breath of air
In the video, you can see a number of penguins briefly popping out of the water as they try to escape the killer whales. This is called "porpoising." It has several functions:
- The penguins can see where they are and where the nearest safety lies. While they can see well under water, they can see further through the air.
- When briefly jumping above the water, the penguins grab a breath of air. Unlike whales and porpoises, which have a blow hole in the top of the head, penguins breathe through their mouths, so they have to get clear of the water.
- When coasting through the air, there is less resistance than when coasting through water. So porpoising saves energy.
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Other cases of animals landing on boats here: Right whale lands on sailboat, South Africa.