The Pajama Shark (Poroderma africanum) is probably the best recognised shark on the planet due to the distinctive dark parallel stripes over a grey body. They can be found along the coastline of South Africa. The small sharks spend a great deal of time as benthic animals, lying amongst kelp Forests and rocky reefs during the day, rising out of these areas at night to hunt for food.

The Pajama Shark is unlike many other large shark species. It is non-aggressive towards humans and plays a vital role in maintaining healthy marine systems. The Pajama Sharks are also favourites with marine biologists, underwater photographers, and ocean enthusiasts alike due to their unique appearance, interesting behaviour, and limited geographic range.

The pajama shark’s camouflage is likely one of its best defense mechanisms. Its striped pattern, as shown below, serves as camouflage for predators and prey alike.

When viewed from a distance among swaying kelp fronds and rock formations, the stripes help break down the silhouette of the shark, making it difficult to see. Other physical characteristics that aid the pajama shark in blending into its environment include:

• Light cream to light brown ground colour
• Flat broad head
• Rounded and short snout
• One pair of barbels located close to each nostril
• Striking cat-like slit with a dark or pale bronze-grey hue
• A flexible body that allows it to fit into narrow crevices

Due to their exceptional camouflage abilities, even experienced divers will occasionally pass by a sleeping pajama shark without realising it.

Compared to some other larger shark species, the pajama shark is relatively small. The average dimensions for a pajama shark are:

• Length: approximately 0.7–0.9 meters
• Maximum length: approximately 1.1 meters
• Weight: typically less than 8kg

Similar to other members of the Scyliorhinidae family, the pajama shark has tough, wrinkled skin that contains dermal denticles. These denticles serve multiple purposes, including helping protect the body from damage when rubbing against sharp rocks and reducing drag. The powerful caudal fin enables the pajama shark to rapidly accelerate but does not enable prolonged high-speed travel.

The pajama shark is a nocturnal hunter and primarily hunts at night. Utilising its acute senses of smell and sight combined with electroreception, the pajama shark searches rocky reefs and kelp beds for concealed prey.

Some of its common prey include:

• Smaller fish
• Octopus
• Squid
• Crabs
• Shrimp
• Lobster
• Worms
• Small rays
• Mollusks

Interestingly, the pajama shark preys upon octopus. Marine researchers have captured video footage showing pajama sharks engaging in lengthy battles with octopuses prior to eventually capturing and consuming them. Due to their intelligence and strength, such battles can be quite intense and dramatic.

Unlike active pursuit predators such as mako sharks, the pajama shark employs a stealth-based hunting method.

Their general hunting techniques include:

• Travelling slowly along the ocean floor
• Searching for prey items behind rocks
• Examine kelp forests
• Detection of electrical signals generated by prey
• Surprise attack on animals hiding in crevices

Given their preference for hunting in low-light conditions and in environments with reduced visibility, their slow-moving hunting technique proves successful.

There are several behaviours exhibited by the pajama shark that are somewhat rare in larger shark species. Some examples of these include:

Daytime behaviour:

• rest in kelp forests
• sleep in caves
• hide under rocks
• group together with other pajama sharks

Night-time activity:

• When evening arrives, they become much more active and leave their resting places to search for food across reefs and sandy seabeds.

Researchers have also noted that some individual pajama sharks exhibit strong site fidelity behaviour (i.e., repeatedly returning to specific resting locations).

The pajama shark produces eggs instead of live births, thus they are classified as oviparous. Female pajama sharks produce distinctive egg cases (also referred to as mermaid purses).

Mermaid’s purses are characterised by:

• Dark brown color
• Long tendrils extending off each end
• Attached to seaweed or rocks
• Protection of the developing embryo

Each egg case encloses a single developing embryo and will develop for several months until it emerges as a completely formed miniature version of the adult pajama shark. Baby pajama sharks are independent immediately upon hatching and receive no parental care.

Despite excellent camouflage, Pajama Sharks have a number of predators.

Some include:

• Larger sharks
• Cape fur seal (Arctocephalus pusillus)
• Large predatory fish

Pajama Shark’s camouflage, nocturnal behaviour and hiding ability among thick kelp help protect the species from detection.

Although Pajama Shark is considered least concerned, there are some human impacts that negatively impact the species.

A major threat includes:

Accidental capture

Pajama Shark is occasionally captured when they become “bycatch” when large-scale commercial fishing operations employ:

• Longlines
• Gillnets
• Bottom trawl nets

While most bycaught fish are returned to the water alive, accidental capture can lead to death.

Habitat destruction/ degradation

A decrease in the amount of habitat for Pajama Shark results in reduced areas for food and shelter.

Possible causes of decreased habitat for Pajama Shark include:

• Marine pollution
• Climate change
• Coastal development
• Marine debris

The Pajama Shark is a prime example of how not all sharks are large predatory ocean animals; rather, this marine animal has an impressive striped appearance, is known for its friendly nature, and possesses many interesting adaptations. This type of information about marine life, such as the Pajama Shark allows people to understand the vast diversity of sharks and their importance in maintaining the health of our world’s oceans.