It turns out that the appealing rodents actually signal to each other using a complex system of whistles and foot-thumping, mostly to warn each other of approaching danger.
Gerbils can claim superiority over their relatives. For example, the communication signals of the great gerbil of central Asia are far more sophisticated than those of their American cousin, the kangaroo rat. When a kangaroo rat meets a threatening snake, it launches into a round of foot stamping to give its kin the simple message: "Stay away." But the gerbil's signals were more along the lines of: "Run for cover, children, there's danger near."
Professor Randall, who studied gerbils in Uzbekistan, deciphered two kinds of whistles and a pattern of accelerating foot drumming. She was also able to "talk" to the animals by playing back tape recordings of their whistles: she found the sounds made the animals head for their burrows faster than usual.
"The kangaroo rats appear to be trying to convince an approaching snake or other predator that they are vigilant and can't be caught," said Professor Randall, an animal behaviourist at San Francisco State University. "But gerbils warn each other of risk."
An upright posture, or moderate rhythmic whistling, made the family members vigilant, but not run away. When an adult doubled the speed of the whistling and foot thumping, relatives headed for the burrows.
The development of complex communication probably derives from gerbils' highly social nature. They live in co-operative family groups, said Professor Randall. Man's early ancestors are thought to have evolved complex language and culture to support social living in the same way.
Kangaroo rats, on the other hand, are solitary animals. They do not respond to their neighbours' foot thumping.
Professor Randall plans to return to Uzbekistan this spring to find out whether gerbils produce different signals in the presence of different predators.