Sexing Success

6/25/14

Chloe Cavanaugh

            Today was our first day out with Professor Mann here, and our second full day of the season. We kicked the morning off with several surveys and a dive follow on two spongers. After lunch we began a mother calf dive follow on Kite and her calf, Otus. The naming theme of their line is birds: Kite’s mother is Kestral, and her other, older calf is Osprey; Otus is Latin for owl.

 Kite and Otus
Photo credit: Ewa Krzyszczyk

           The three-hour follow stretched through a beautiful afternoon: rays of sun broke through the clouds onto the distant ocean and the water was smooth as silk. Kite, a known sponger, sponged for the first half hour of the follow, and then switched to snacking, a foraging tactic in which dolphins chase a fish up to the surface and go belly up to trap it there while they catch it. Often with snacking bouts we see the fish breaking the surface or even jumping out of the water in an attempt to escape. Otus never picked up a sponge, but the calf did join the mother in snacking bouts and other dive foraging later on. We hoped Otus would bowride so we could sex it, but the two never came over to the boat.

A calf snacking belly up in pursuit of a fish

Photo credit: Ewa Krzyszczyk

            The setting sun turned the water to liquid gold as we neared the end of the follow. The light was fading fast, but Professor Mann was determined to sex Otus. We did one last survey of several dolphins that had joined up with our two at the end of the follow. Finally, Kite and Otus came over to bowride—Professor Mann and Eric rushed to the bow, leaning over the edge, but Otus wouldn’t roll over onto its back. He swam off and came back again, and this dance was repeated a few more times. Then, right before darting away for good, Otus barrel-rolled, giving Professor Mann the one glance she needed.

           “Long gen slit, big gap, no mamms, grade A view!” she cheered, with high-fives all around. Otus was officially a boy. 

A ventral shot of a male dolphin with long genital slit clearly visible.

This individual has a scratch of unknown origin to the left of its genitals.

Photo credit: Ewa Krzyszczyk