About a week ago while walking around Medicine Lake (Siskiyou County CA) I noticed hundreds of little toads in the grass near the shore. There were so many that I had to tread carefully to not squash one of these young amphibians.
Toads, like frogs, begin life in an aquatic habitat and transition to land. Most mate in the water , where their eggs are laid and the tadpoles hatch. The tadpoles begin life with an ovoid body, long tail and external gills. As the larvae metamorphose into a toad, the external gills are replaced by internal lungs, the tail is reabsorbed, a wide mouth forms and legs emerge, among other changes. During metamorphosis the young toads inhabit shallow water where both gill and lung respiration are possible, eventually emerging on land as juvenile toads.
The juvenile toads at Medicine Lake were western toads (Anaxyrus boreas). Although these youngsters were less than an inch long, adults can grow to between 2″ and 5″ in length. Toads have warty, dry skin. The coloring of a western toad is green, tan, grey or reddish-brown – quite variable. Its rusty colored warts are usually set on black blotches. The pupils are horizontal and there is a light-colored stripe down the center of the western toad’s back. The underside is light and blotchy. Juveniles have yellow on their feet.
Western toads have an oval, rusty-colored parotoid gland behind each eye. Parotoid glands secrete a milky alkaloid substance to deter predators. The substance, bufotoxin, acts as a neurotoxin. Although it deters some predators, other predators are immune to bufotoxin and consume toads. Other predators, for example ravens, avoid the poison by only eating the toad’s viscera through its abdomen.
Western toads eat a variety of invertebrates including worms, ants, spiders, beetles and moths. The prey is located by sight and then the toad lunges and extends its long, sticky tongue to capture the prey and bring it to its mouth.
Western toads inhabit a variety of habitats including lakes, woodlands, forests, desert riparian areas, springs, marshes and creeks throughout the west from sea level to over 11,000 feet.
Until 2006 the western toad was known as Bufo boreas. At that time it was split off into the genus Anaxyrus. Many people continue to use Bufo as the genus name, but Anaxyrus is currently the correct name. There are several subspecies of western toad with different common names. Although boreal toad and California toad are common names of these subspecies, all the subspecies can be grouped together as western toads. The scientific name for the western toad derives from the Greek: “anaxyrus” meaning “king or chief” and “boreas” meaning “northern”, referring to the northern range.
The toad on its back in my hand was not harmed. After many attempts, I finally managed to turn it on its back and have it remain still long enough to get the camera focused and snap a picture with the other hand. It happily rejoined its friends after the photo session.