A sperm whale entertained volunteers with the American Cetacean Society's Los Angeles Chapter Gray Whale Census during the final hours of the day, according to a post on the Facebook page.
The sperm whale made two dives of about 30 minutes apiece, and did a headstand as it fluked and dove each time. (Watch the YouTube video above to see the whale dive.)
"You (could) see its distinctive angular blow, rounded head and dorsal hump, knuckles, and huge fluke raised slowly and held high as it dove straight down," researcher and census coordinator Alisa Schulman-Janiger wrote on the ACS/LA Facebook page. "WOW!"
Schulman-Janiger estimated that the whale came within a mile of Point Vicente, where the Gray Whale Census is based.
She also said that she hoped the sperm whale will "stick around over the next few weeks, foraging on squid over our nearshore canyon."
The sperm whale is the largest toothed whale. Mature males are about 50 feet in length, and the whales will dive up to 9,800 feet for food.
Though no gray whales were sighted Monday, census volunteers did spot common, Pacific white-sided, Risso's and bottlenose dolphins, in addition to a trio of fin whales. A pod of orcas was also seen over the weekend.