20 frog facts

You prob­a­bly learned the frog life­cy­cle at school. Here are some facts your teacher won’t have men­tioned

World of Animals - - What's Inside -

1. Some trop­i­cal frogs are ab­so­lutely lethal

Poi­son dart frogs are the most poi­sonous ver­te­brates in the world. Their name comes from the use of their poi­son by South Amer­i­can hun­ters to lace the tips of blow darts. The toxin se­creted from the skin of the 5.5-cen­time­tre (2.2-inch) golden poi­son dart frog is strong enough to kill ten men.

2. Males make them­selves heard

Male frogs croak and call to at­tract fe­males and let other males know that they’ve claimed a ter­ri­tory. The calls show off how healthy po­ten­tial suitors are, and some are so loud they can be heard 1.6 kilo­me­tres (one mile) away.

3. You won’t see many frogs in win­ter

Frogs can es­cape the cold of win­ter by hi­ber­nat­ing un­der­wa­ter or bur­row­ing into the soil. While they sleep, a new layer of growth forms on their bones, cre­at­ing age rings sim­i­lar to the ones found in trees. Some species, like the wood frogs, hide among leaf lit­ter and let their bod­ies freeze. Their hearts stop beat­ing, their blood stops flow­ing and up to 65 per cent of the wa­ter in their body freezes, but come spring they thaw and hop off.

5. Not all frogs hop – some walk and run, and waxy tree frogs grip branches with op­pos­able toes and move like chameleons.

6. The world’s largest frog is the Go­liath frog. It can grow to 32 cen­time­tres (12.6 inches) in length and weigh as much as a new­born baby.

7. Frogs don’t drink through their mouths; they ab­sorb the wa­ter they need through their per­me­able skin. Many have an ex­tra thin patch on their un­der­side known as a drink­ing patch.

8. Toads are frogs. They all be­long to the or­der Anura – toads are just frogs with short legs and dry, bumpy skin.

4. Am­phib­ians have ex­isted for around 395 mil­lion years, and frogs first hopped onto the scene around 190 mil­lion years ago.

9. The Egyp­tians had a frog god­dess

Frogs were con­sid­ered sym­bols of fer­til­ity in an­cient Egypt, as they were as­so­ci­ated with the yearly flood­ing of the Nile. He­qet, the god­dess of fer­til­ity and child­birth, was usu­ally de­picted as a frog or a frog­headed woman.

10. Frogs swal­low with their eyes

With their round, bulging eyes, frogs can see in al­most every di­rec­tion at once.

They also have an ex­tra eye­lid. Known as a nic­ti­tat­ing mem­brane, it is semi­trans­par­ent and both lu­bri­cates the eye and pro­tects it un­der­wa­ter. When a frog is swal­low­ing a par­tic­u­larly large piece of food it will blink hard, forc­ing its eyes back into its head to help push the food down.

11. Frogs can’t chew their food

While our tongues are at­tached to the back of our throat, a frog’s tongue be­gins at the front of its mouth. This al­lows the frog to throw its sticky tongue out as far as pos­si­ble when it’s hunt­ing in­sects. Lack­ing teeth suit­able for chew­ing, ev­ery­thing it catches is swal­lowed whole. 13. Tad­poles are wary Some tree frogs lay their eggs on leaves above rivers and streams. If the tad­poles sense dan­ger, they can quickly wig­gle out and drop into the wa­ter.

18. There are around 4,740 species of frog known to science, liv­ing in habi­tats rang­ing from ponds and lakes to trees and grass­lands. 19. Male Dar­win’s frogs take their pa­ter­nal du­ties se­ri­ously

A fe­male Dar­win’s frog lays around 40 eggs in leaf lit­ter be­fore the fa­ther takes up po­si­tion as guard. When the grow­ing young be­gin to move, the male in­gests the eggs so they can go through the re­main­ing stages of de­vel­op­ment in the safety of his vo­cal sac. Two months later, small frogs hop out of his mouth and set off into the for­est. 12. Some frogs are see-through Glass frogs live up to their name. These lit­tle tree frogs have trans­par­ent skin, leav­ing all their in­ter­nal or­gans on show.

14. The round patches of skin lo­cated on a frog’s

head just be­hind the eyes are the tym­pa­nums. These non-glan­du­lar skin mem­branes trans­mit sound waves from the air to the

frog’s in­ner ear.

15. The Bornean flat­headed frog is the first frog dis­cov­ered to have no lungs. Rather than breath­ing, it takes in all the oxy­gen it needs through its skin.

16. In me­dieval times frogs were con­sid­ered to be signs of the devil and ac­com­plices of witches. These su­per­sti­tions might have arisen from the warty skin of toads and the toxic se­cre­tions they pro­duce to

ward off preda­tors.

17. Many frogs can use their strong legs to cover more than 20 times their own body

length in a sin­gle jump.

20. Frogs will eat their own skin

Frogs pe­ri­od­i­cally moult to fend off in­fec­tions and keep their bod­ies in good con­di­tion. Rather than wast­ing it, they’ll eat the shed skin to re­gain some of the nu­tri­ents. In some species the skin is cov­ered with mu­cous or a waxy coat­ing to trap mois­ture.

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