|Red-bellied newt distribution|
When full grown, the red-bellied newt measures between 2.75 to 3.5 in (70 to 89 mm) from its nose to its vent, and between 5.5 and 7.5 in (140 and 190 mm) from nose to tail. It has grainy skin, and is brownish-black on top with a tomato-red underbelly. It can be distinguished from other coastal newts by its red belly and a lack of yellow in its eyes. Breeding males develop smooth skin and a flattened tail.
Distribution and habitat
The Red-bellied newt is found in California along the coast from Bodega in Sonoma County, inland to Lower Lake, and north to Honeydew, Humboldt County. It lives in coastal woodlands, especially in redwood forests.
Reproduction and ecology
Red-bellied newts lay their eggs in fast-flowing streams or rocky rivers. Newts begin their lives as aquatic larvae similar to tadpoles, though elongated and with external gills. Once they have matured into the adult form, which takes about four months, and usually happens in August, they leave the water until the fifth year of their lives. Then, as early as January or February, the males start congregating at stream banks. One to three weeks later, the females join them and the newts mate. The females lay their eggs in about 12 streamlined clusters with six to 16 eggs each. They usually lay them on the bottoms of rocks, or on branches leaning into the stream. When the adults leave the stream, instead of moving directly uphill, they move at an angle that leads them somewhat upstream. The females, unlike the males, do not breed every year. Red-bellied newts can live for up to 15 years.
Red-bellied newts have a remarkable homing ability. They make great efforts to always go back to the same spot on the stream. They find their way over several miles of rugged terrain to get back to the spot. Likely, smell is responsible for the homing ability.
Red-bellied newts have a brownish-black topside to avoid being noticed. When that fails, and they are seen and disturbed, they pull their heads and tails back to reveal their bright-red undersides. This serves as a warning to potential predators, as red-bellied newts have enough of a neurotoxin, tetrodotoxin, in their skin to easily kill an adult human, or 7,500 mice. Like other newts, red-bellied newts have the ability to regenerate several body parts, including their limbs, eyes, hearts, intestines, upper and lower jaws, and damaged spinal cords.
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