Toads and Frogs

Toads and frogs are believed by many experts to be the new canaries of the world. (You probably have to think on that one!) In all seriousness, however, canaries were taken into coal mines to alert miners to carbon monoxide gas in the mines. If the canaries died, the miners knew that it was time to vacate the premises. The carbon monoxide killed the canaries at such a low concentration that the miners had time to escape before being overcome by the gas.

Many scientists today believe that the disappearance of many species of toads and frogs combined with an alarming number of malformed young ones is a warning to us, as humans, that we'd better clean up our act.

It is a belief by many that depletion of ozone levels, pesticide residues, smoke and smog are contributing factors in the loss of these environmentally valuable amphibians. Are toads and frogs truly the new canaries for the whole human race? I don't know. I do know that it's difficult to appreciate and respect a species if you know nothing about it. Thus the reason for this column.

Of 24 species of frogs and toads in California, one, the Arroyo toad, is Federally endangered. 15 other species have shown declines in their populations so that they are, at the very least, species of "special concern" either in California, nationally or worldwide. Things don't sound too promising for our frogs and toads, do they?

Now, the two most important questions from you readers will surely be 1) Which ones give us warts? And 2) Which ones do we kiss to find our prince? The answer to both questions is "neither".

With that out of the way, let's concentrate on the facts. Frogs and toads are amphibians. "Amphibian" comes from the Greek meaning "both life". Amphibians can live on water and on land.

Toads are mostly land-dwelling animals with thick, warty skin. Although they need moisture, it is generally less than what frogs require. Toads are found in fields, gardens, meadows and woodlands. Toads do not jump as much as frogs. They generally do short hops or "walks", and usually have squat bodies and short legs. They use bodies of water for reproduction, and lay from 20,000 to 100,000 eggs at a time. Their larval stage are tadpoles- water-dwelling, tailed creatures, so unlike the adults. Two species of toads do not adhere to the toad rules of reproduction. One toad lays its eggs on the ground and does not have a tadpole stage. Another species gives birth to fully-formed small toads! Odd creatures, indeed.

Toads can hibernate for several months inside burrows which they dig with their hind feet. So now we know where they are until our "supposed" El Nino rains come!

Toads can secrete a poison from their skin to ward off predators. These toxins can often kill dogs and cats who haven't learned of the toxicity. The wary wild predators (skunks and raccoons) often roll toads in the dirt to get rid of these secretions prior to dining. Toads are often preyed upon by snakes, but the toad has the ability to inflate himself in order to become one tough customer for that snake to swallow!

Adult amphibians eat live, moving animals such as insects, crustaceans, worms, and mollusks. Larger species will eat birds, small fish and small mammals. The aquatic larvae of toads and frogs (tadpoles) feed on algae and bits of dead animal matter in the water.

Frogs have long hind legs which allow them to jump. They can leap 2 to 10 times their body length, and some species can leap up to 40 times their body length. The California Red-legged frog, now classified as Federally threatened, is the celebrated jumping frog made famous by Mark Twain. Once numerous, their populations are now found mostly in 3 California counties. Tragically enough, one reason for their decline lies in the fact that, in years past, over 80,000 frogs were harvested annually for their legs. Facing a decline in these frogs for restaurant use, the bullfrog was introduced to supply frog legs to restaurants in California. Unfortunately, the voracious bullfrog thrives on the eggs of the California Red- legged frog and replaces them in their habitat. It sure sounds like 2 strikes against this famous frog, doesn't it?

In my research for this column, I found some interesting "factoids" on frogs, toads and other amphibians that I thought you'd enjoy:

• Frogs are cold-blooded, thus their body temperatures are easily affected by their surroundings. However, some frogs can survive incredibly cold temperatures. With as much as 65% of their body water frozen as ice, these frogs can survive due to chemicals in their body which prevent them from freezing to death.
  
  
• Frogs are either tongued or tongueless. Tongueless species gulp their prey while tongued species extend their tongue to catch prey. Glands at the top of the tongue hold the prey as it is drawn into the mouth.
  
  
• Young, dispersal aged toads and frogs often create roadway hazards as they emerge from their natal ponds in search of their terrestrial habitats. Emerging by the thousands, these youngsters make streets and roadways slippery and dangerous.
  
  
• Frogs and toads have been known to clog water outlets and lawn sprinkler systems.
  
  
• While a decline in local populations of frogs can often be explained due to pesticide run-off or the drought in California, scientists cannot agree on the reasons for a worldwide decline. Why would an animal who has been on Earth for 200 million years start declining in numbers today?
  
  
• Frogs aren't the only amphibians in decline. Scientists are now reporting a global decline of salamanders, newts and toads.
  
  
• Is it a toad or a frog? This can be very confusing, especially when one notes that the Mexican burrowing toad, the Surinam toad, the fire-bellied toad and the midwife toad are really not toads at all!
  
  
• With our most recent rains, we were so looking forward to the "Amphibian Chorus" that lives in our yard. It's so comforting to know that they are there keeping our plants healthy by controlling our insect populations. For some strange reason, there was no song with this rain.
  
  

Thanks to Carol Tov, for the column idea. If any of you have any questions about native wildlife or suggestions for future columns, please pass them along to me.

For the reader with the bee problem: citronella candles and smoke are the only humane deterrents I've been able to find. Good luck!

Roxanne Davis, we think your mystery hawk is a black-shouldered kite. Look for a future column on this beautiful bird of prey.

— Cindy Traisi