California Spiny Lobster (Panulirus interruptus)

[orrickvang]

are they trying to mate?

[CaliforniaDFG]

"It is impossible to tell from the video alone whether this is in fact a male pursuing a female in order to secure a packet of sperm to the female's underside. Closer inspection of the animals would be necessary to determine sex, and a longer period of observation would be required to determine exactly what behavior the animals are exhibiting in this short video.

[CaliforniaDFG]

(continued...) Other possibilities also exist, including the possibility that the animals are lining up to migrate together, or that they are simply reacting to escape the light being shown on them, trying to find a dark space in the reef to hide in." -- Travis Buck, DFG Marine Biologist