Like some sharks, spotted ratfish are oviparous. Their spawning season peaks during the spring to autumn. During this time, the female releases up to two fertilized eggs into sand or mud areas of the seabed every 10–14 days. The extrusion process can last 18–30 hours and the actual laying can last another 4–6 days. The egg sack is leather-like, long, and has a filament connected to it which is used to attach it to the ocean floor when it is let go by the mother. A female may be seen swimming around her newly laid eggs, in hopes of preventing predators from finding them. Development of the egg can take up to a year, which can be dangerous because the eggs are sometimes mistaken for inanimate objects by divers. When the young finally hatch, they are about in length and grow, reaching in length their first year.