You see, penguins in zoos are not given an environment with sufficiently deep water into which they may achieve a depth of dive that will attain extreme inner ear pressures necessary to produce exclusively heterosexual fantasies and desires. Or so my Roman Catholic priest uncle informed me and the other altar boys so many years ago.
On Japanese TV yesterday, they were talking about how, in some species of frog, sometimes a male mounts another male. When that happens, it's up to the "mountee" to "sing the appropriate song" and get the other fella down. I found it interesting that the ability to discriminate between sexes can be so ... limited.
Then while reading,
"Individual Development & Evolution" (Gottlieb) p. 167 writes:
Another remarkable organism--environment coaction occurs routinely in coral reef fish. These fish live in spatially well-defined, social groups in which there are many females and few males. When a male dies or is otherwise removed from the group, one of the females initiates a sex reversal over a period of about two days in which she develops the coloration, behavior, and gonadal physiology and anatomy of a fully functioning male (Shapiro, 1981).