The whale shark on the sock

The blue sock in the Deep Water Guardian trio carries a whale shark, with a row of bubbles knitted around the cuff. Here is the animal behind it.

The largest fish in the sea

A whale shark is a shark, not a whale, and it is the biggest fish alive. It feeds on plankton, krill and small fish, which it filters from the water while swimming slowly with its mouth open. The pattern of pale spots on its back is different on every animal. Researchers photograph the spots and use them the way we use fingerprints, to tell one whale shark from another across years and oceans.

Ningaloo, from March to July

Every year, from about March to July, whale sharks gather off Ningaloo Reef, some 1,200 km north of Perth. They feed near the surface there, which is why people can swim beside them. Tags fitted to whale sharks show they also go far below it. The deepest dive recorded so far is 1,928 m, in water at about 4 °C.

On the sock

The whale shark is knitted in blue, as part of the fabric rather than printed on it, so the picture keeps its shape and colour wash after wash. The yarn is 85% cotton, 12% nylon and 3% elastane, and one size fits most adult feet. The whale shark sock is sold on its own or in the trio with the octopus and the sea turtle, on the Deep Water Guardian socks page. Every order is posted from Perth with Australia Post; here is how long that takes, state by state.