Long after the water had been emptied out of Deadlock's lungs, and the pack had trotted off for the long uphill climb to the railway station, the gulls were flying over something in the sea beyond the mouth of the little estuary. Sometimes one dropped its yellow webs to alight on the water; always it flew up again into the restless, wailing throng, startled by the snaps of white teeth. A cargo steamer was passing up the Severn Sea, leaving a long smudge of smoke on the horizon, where a low line of clouds billowed over the coast of Wales. The regular thumps of its screw in the windless blue calm were borne to where Tarka lay, drowsy and content, but watching the pale yellow eyes of the nearest bird. At last the gulls grew tired of seeing only his eyes, and flew back to their posts; and turning on his back, Tarka yawned and stretched himself, and floated at his ease. CHAPTER SIXTEEN Swimming towards the sunset Tarka found a cleft in the high curved red cliff, and on the crest of a wave rode into the cavern beyond. The broken wave slapped against the dark end as he climbed to a ledge far above the lipping of the swell, and curled himself on cold stone. He awoke when the gulls and cormorants were flying over the sea, silent as dusk, to their roosts in the cliff. The straight wavelets of the rising tide were moving across the rock pools below the cleft, where under green and purple laver-weed crabs and prawns were stirring to feed. The weed, so placid before, was kicked and entangled by the searching otter. The crab he climbed out with was bitter, and leaving it, he swam into deep water. A herring shoal was coming up with the evening tide, followed by a herd of porpoises, which when breathing showed shiny black hides through the waves. Fishermen called them errin-ogs. Once these warm-blooded mammals had ears and hair and paws, but now their ear-holes were small as thorn-pricks, and their five-toed paws were changed into flippers. Their forefathers, who had come from the same family as the forefathers of otters and seals, had taken early to water, shaping themselves for a sea-life while yet the seals were running on land. Their young, born under water, needed no mother's back to raise them to the air of life, for ancestral habit had become instinct. An old boar porpoise flung himself out of a trough near Tarka and fell with a clapping splash on its back, to shake off the barnacle-like parasites boring into its blubber. Near the boar swam a sow porpoise, suckling her little one, who, towed along on its back, breathed during every rise and roll of its mother. Tarka caught his first herring and ate it on a rock, liking the taste, but when he swam out for more, the under-seas were vacant.