The second termite caste, for which there is no parallel among the ants, consists of both males and females with only rudiments of wings, less fully developed reproductive organs, and somewhat smaller eyes and brains. They presumably serve only as an auxiliary royalty, functioning in case the true rulers die. Apparently by some subtle alchemy known only to termites they can be transformed into fully functioning sexual individuals if an emergency arises.
A third caste is made up of smaller insects with extremely minute eyes and brains and barely discernible reproductive organs. Below them come the entirely unpigmented, soft-bodied workers with still smaller eyes and brains—usually, in fact, with no eyes at all. These still are potentially males and females, in distinction to any society where all workers and soldiers are female. Lowest in the scale are the big-headed, blind soldiers, also of both sexes, with barely a trace of brain.
Relative numbers in these castes differ from species to species. An analysis of an Australian termite colony accounted for 1,560,500 workers, 200,000 soldiers, and 44,000 potentially reproductive individuals.
The Shark That Stands Upright
Monster of Gulf of Mexico waters is a shark which weights from ten to twelve tons and is from 30 to 50 feet long. Largest of its ancient family and an entirely inoffensive creature, this strange animal literally stands upright while feeding.
On a recent trip a U. S. Fish and Wildlife Service ship encountered several large schools of black-finned tuna. In the middle of each school was a large object which looked like a barrel. This object was the snout of a whale shark.
The creature kept opening its enormous mouth two or three inches below the surface. From 50 to 100 gallons of water would flow into the mouth and be strained out through the gills. This water was full of larval crustaceans, or banded shrimps, about a half-inch long.
In each observed case the body of the shark stood vertically. Why each shark should select a school of tuna and put itself almost precisely in the center of the swarming fish is a complete mystery. It does not eat tuna, except possibly very small ones. Presumably, however, it feeds on about the same sort of material as the fish. It knows there is food where the tuna congregate.
The whale shark is among the most mysterious of the larger sea animals. It is a solitary creature, seldom seen. Its tiny teeth are only about one fifteenth of an inch long and it is supposedly entirely a feeder on plankton, the minute organisms which abound in sea water.