The Swell Shark (Cephaloscyllium ventriosum) is a type of catshark found in the Eastern Pacific Ocean. They are oviparous, meaning that the females lay eggs – a common feature of bottom-dwelling sharks. The eggs are laid as a pair and will hatch within 7 to 10 months depending on water temperature. The young pups average 14cm (5 inches) long at birth and will grow to a maximum size of 87cm (~3 ft).
The eggs of a Swell Shark are a brownish/amber color and are translucent. By shining a light behind the egg (known as ‘candling’), we can monitor the development of the embryo. Once ready to hatch, the pup uses enlarged ridges on its back to cut the egg open and swim free. Once they reach a foot in length, these enlarged ridges disappear.
The Minnesota Zoo currently has three adult Swell Sharks for the public to view in the Estuary exhibit. While they generally like to rest on the bottom, you might have the unique chance of touching one if they happen to be swimming around.