Although the axolotl remains in larval form throughout its life, it becomes sexually mature between 12 and 18 months of age. Males 'dance' to initiate courtship, nudging the female before depositing several cone-shaped packets of sperm known as spermatophores onto rocks and plants. These are taken up by the female's cloaca, for internal fertilisation of her eggs. She lays the eggs 24 hours later, each one becoming enveloped in mucus as it emerges. They become glued to each other and to the substrate (3) where they incubate for two to three weeks (2). A single female can produce up to 400 eggs in a day, averaging 175 – 200 (3). The axolotl is inactive during the day, resting on the substrate with the gills splayed. They move slowly and may surface occasionally to take a breath of air (3). Young axolotl feed on algae, but older individuals will take aquatic invertebrates. The axolotl is primarily preyed upon by herons (2). A species of fascination to scientists the world over, the axolotl has many study-worthy traits. Whilst able to remain in larval form throughout its life, the axolotl can metamorphose into a fully-adult Mexican salamander if its habitat dries up. Additionally, rather than forming scar tissue when wounded, tissues at the wound site convert to a stem cell-like state, meaning that they are able to re-grow missing tissue in its entirety, even a whole limb (3).