Newt
During the subsequent few months, the larvae undergo metamorphosis, during which they develop legs, and the gills are absorbed and replaced by air-breathing lungs. Some species, such as the North American newts, also become more brightly coloured during this phase. Once fully metamorphosised, they leave the water and live a terrestrial life, when they are known as "efts". Only when the eft reaches adulthood will the North American species return to live in water, rarely venturing back onto the land. Conversely, most European species live their adult lives on land and only visit water to breed.
Red-bellied newt
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.