Territorial bull sea lions send clear warning to swimmers

Swimmers in the Galapagos Islands took advantage of a sunny day and a break between scuba dives to enjoy a dip in an inviting cove. The water was a beautiful blue and the sheltered bay was home to a colony of sea lions that were basking on the shore nearby. Two playful sea lions ventured out to meet the swimmers and they looped and swirled all around them for a few moments before darting back toward the shore.
Mesmerized, the swimmers followed the curious and energetic young sea lions and they watched from afar as the sea lions in the colony swam back and forth along the edge of the island. But two of the sea lions were not playful youngsters or tolerant females. The two larger sea lions have the well developed bone crest on their head that tells observers that they are mature males, and full of testosterone. With the increased hormones comes increased territorial aggression. These swimmers quickly found that the younger male was curious and he made a few close passes to inspect them. This seemed harmless enough and he made no move to suggest irritation. But another bull showed up and he turned out to be the dominant male of this colony.Show more

Bull sea lions have little sense of playfulness and they are likely to engage in challenging behaviour such as swimming directly at animals near their females. The bull in this case made a few close passes and even opened his mouth, grunting or barking. On one pass, the bull opened wide and snapped at the swimmer in what appears to be a half serious attempt to bite.

Sea lions are extremely agile in the water and they can swim circles around a clumsy human, much faster than one would expect, considering their large and blubbery physiques. Realizing that they were unwelcome, these swimmers backed away and kept a greater distance from the colony. This was the message that the sea lion was sending and he was satisfied that they had understood his warning.

Sea lions are a joy to watch, and the younger sea lions, as well as the females are likely to approach swimmers and invite them to play. They will dart back and forth, nearly touching humans. They loop and dive and then hang suspended upside down while they stare at people. They almost seem to be smiling and few can resist a friendly invitation to play with them.