Polk County Conservation

Amphibians

Bull frog

The term “amphibia” means double life. It refers to the fact that all amphibians spend part of their lives in water and part on land.

Amphibians were the first vertebrates to leave the water and live on land. However, they are still very dependent on water for reproduction. All amphibians lay their eggs in water or wet areas. Their eggs, similar to fish eggs, have no outside shell. These small round eggs are soft and squishy, similar to gelatin, and need to stay in a moist place so they don’t dry out.

Breeding for most amphibians is seasonal, based on temperature and availability of water. Young amphibians go through a remarkable metamorphosis, or period of change. After hatching, the young amphibian stays in a larval stage for a period of time before maturing to an adult. In the larval stage, they have gills to obtain oxygen from the water.

The skin of most amphibians is smooth and contains numerous mucous and toxic glands, giving them a moist, slimy feel. Adults breathe with lungs, but in some cases their lungs are so poorly developed they also absorb oxygen through their moist skin.

Frogs and Toads

Toads and frogs are closely related. Not sure if you’re looking at a toad or frog? Call it a frog and you’ll be right! Some of Iowa’s 16 species are quite terrestrial or land loving (the toads) while others move only short distances from water (bullfrogs).

One of the first signs of spring is the call of the western chorus frog. While it may be only an inch long, it makes a big noise. The chorus frog isn't really singing in a chorus, it's a male frog looking for a mate. Each male frog moves away from its calling neighbors to establish a few feet of marsh to call his own.

A good place to hear and see frogs and toads is Chichaqua Bottoms Greenbelt. Each spring and summer the woodlands erupt with their variety of songs. You can also discover frogs in various stages of development in the small ponds at Jester Park. From eggs to giant bull frogs all are waiting to be discovered!

Salamanders

Salamanders are considered the most primitive of living amphibians. Some have changed little from those that roamed the earth 270 million years ago. Five species live in Iowa.

Mudpuppies remain aquatic their entire life. They are the largest of Iowa’s salamanders and even though they develop lungs, they retain three pairs of feathery gills.

The central newt is Iowa’s smallest salamander. They have a complicated life cycle involving eggs, very small aquatic larvae, terrestrial subadults called efts and mature aquatic adults. Both adults and efts have skin secretions that are irritants and may be toxic to other animals.

Tiger salamanders are found in nearly any non-flowing body of water in Iowa. They are essentially black with abundant yellow or cream colored dots.

Smallmouth salamanders occur in most of southern Iowa. Because of the continuing loss of small pools in Iowa’s woodlands, this species may be declining.

The blue-spotted salamander is a state endangered species. It is a medium-sized salamander which is easily recognized by bluish-white markings. Iowa’s two small known populations are being closely studied.

Salamanders are quite secretive and are very rarely seen. Occasionally you might see a tiger salamander slinking through the grass at Sandhill Prairie, located north of Bondurant.

Links

  • Iowa Herpetology - This site is designed to introduce you to the herpetology of Iowa. Contains pictures, information, and distribution of amphibians.
  • www.allaboutfrogs.org – a very good site with frog sounds, facts, games, jokes, and conservation concerns.

Contact Us

Administration Office
11407 NW Jester Park Drive
Granger, IA 50109

P: (515) 323-5300
F: (515) 323-5354
pccb_info@polkcountyiowa.gov

Monday – Friday, 8:00 a.m. – 4:30 p.m.

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