Whale Shark

Whale Shark battle analysis

The whale shark is a giant built for patience. A mature female stretches around 12 metres and weighs roughly 15 tonnes, yet she feeds on some of the smallest animals in the sea, cruising open-mouthed through plankton or hanging vertically to gulp fish eggs. Her hundreds of rows of tiny teeth are never used for eating; the real work is done by the filter pads behind them.

In a battle, that makes the whale shark a pure defender. Its skin is among the thickest of any animal, covered in denticles, and its eyes are armored with thousands of tiny tooth-like scales and can be pulled back into the head. A lone shark or seal-hunter would struggle to do more than scratch it. When things go badly, it can dive: tags show whale sharks plunging to around 2,000 metres, deeper than almost any opponent could follow.

What the whale shark cannot do is hurt anything on purpose. It has no bite, no spines and no fighting behavior, and it swims so slowly that a determined attacker can stay with it indefinitely. Orcas in the Gulf of California have learned exactly that, working together to open the soft pelvic region. Against a single predator the whale shark simply outlasts the attack; against a coordinated pack, its armor eventually runs out.

Habitat & range

Whale sharks live in tropical and warm-temperate seas worldwide, both far offshore and at predictable coastal feeding hotspots such as Ningaloo Reef, the Yucatán Peninsula, La Paz, Mozambique, the Philippines and the Arabian Gulf. They move between surface waters and the deep sea, occasionally diving to about 2,000 m.

Diet & hunting

The whale shark is a filter feeder. It eats plankton, krill, fish eggs, small schooling fish and squid, either by swimming slowly open-mouthed or by hanging vertically and sucking water in. It follows seasonal food pulses: coral spawning at Ningaloo, fish-spawn events around offshore platforms in Qatar and plankton blooms in the Gulf of California.

Social life

Whale sharks are solitary but gather in large numbers where food is concentrated. These aggregations are feeding gatherings, not social groups, and are often dominated by juvenile males.

Conservation

The whale shark is listed as Endangered on the IUCN Red List (Pierce and Norman 2016), with estimated declines of more than half over three generations in the Indo-Pacific, driven by fisheries, bycatch and ship strikes. The Atlantic subpopulation was assessed separately as Vulnerable. It is listed on the Convention on Migratory Species appendices.

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