Humans have fantasized for years about the time when they would be able to deep-freeze someone and restore him to life sometime in the future. For some frogs, however, this is no fantasy. They do it every year.
Like other animals, frogs are faced with the problem of surviving winter without central heating or hearth fires. Their solution? They “just squat in the open until they freeze solid,” says a report in The Toronto Star. When spring comes around, the frog thaws out and starts croaking again.
Why doesn’t the freezing kill him? Biologist Kenneth Storey says: “We found frogs produce an anti-freeze molecule that we didn’t expect at all: glucose. People had said there was no way to use that as an anti-freeze, but frogs can.” Seemingly, because of this glucose, when the frog freezes, its tissue fluids turn to syrup instead of forming ice crystals that would expand and rupture its cells.
The magazine Science Digest reports that certain creatures in Antarctica have a natural antifreeze that helps them keep moving in cold weather. However, when the temperature gets too low, they freeze and die. A tiny wingless fly—whose name, Belgica antarctica, is much bigger than he is—also uses the natural antifreeze to keep moving in ordinary cold weather. But when very cold weather threatens, he uses an “anti-antifreeze” chemical to survive. Long before the temperature gets dangerously low, the “anti-antifreeze” stops the action of the antifreeze. Why?
Biologist John Baust explains: “By inducing the insect to freeze at fairly warm temperatures, the special anti-antifreeze compound insures that ice forms at a slow rate. At lower temperatures, rapid freezing would remove water from its cells too quickly, and the animal would die as a result.” But since Belgica antarctica freezes gently, he survives and simply thaws out when the temperature rises again.
And the Smart Potato!
A perennial problem for farmers is controlling infestation by aphids such as the greenfly. According to a report in the Daily Mail, it seems that one type of potato has solved the problem all by itself.
Scientists in Hertfordshire, England, discovered that the potato plant Solanum berthaultii produces a chemical that is exactly the same as that given off by a dying aphid to warn other aphids. The plant is left in peace as aphids, alarmed by the chemical, give it a wide berth.