This week’s featured species is the ornate wobbegong (Orectolobus ornatus). This beautifully tasseled shark is a member of the order Orectolobiformes which contains 31 species in 7 different families including carpet sharks, wobbegongs, epaulette sharks, nurse sharks, blind sharks, and zebra sharks (Parker, 2008). This order also contains the family Rhincodontidae which contains a single species: Rhincodon typus, the whale shark (Parker, 2008)! So the ornate wobbegong is actually a cousin of the largest shark on earth!
The ornate wobbegongs are the family Orectolobidae, which contains 12 species of wobbegongs. Like all “wobbies,” the ornate wobbegong has a flattened body with a broad head and back that quickly narrows towards the tail. They have long, slender teeth that have been adapted for grasping small, benthic fishes. What differentiates the ornate wobbegong are the black bordered, saddle-like markings along its back side. It has 5 to 6 dermal lobes on each side of its head and a single barbel attached to its nostril. Other species of wobbegongs like the tasseled wobbegong (Eucrossorhinus dasypogon) can have dermal lobes covering the lower jaw and chin and several barbels instead of one (Tricas, Deacon, Last, McCosker, Walker, Taylor, 1997).
Most people have heard that if a shark stops moving it will die. For the majority of sharks, that is true. Many sharks breathe through a process called ram breathing where the process of moving forward forces oxygen rich water over the gills and allows them to breathe. However, this isn’t true for wobbegongs. Wobbies have a modified system that allows them to breathe through a hole called a spiracle located just behind each eye. The spiracle pulls oxygenated water down over the gills, allowing the motionless wobbegong to breathe (Parker, 2008). Skates and ray also spiracles to pass water over their gills when resting at the bottom.
So why does the wobbegong look so weird? It certainly doesn’t have a typical shark appearance. Well that’s because it doesn’t have a typical shark life. They spend the majority of their lives lying perfectly still on the seafloor, waiting for prey to come to them (Angela, Angela, & Recchi, 1998). They are ambush predators. They have been known to raise and wiggle the large, swooping upper lobe of their tail like a fish or fan of algae, welcoming a fish to swim over the shark’s head. They also wiggle the fronds on their head gently to attract fishes and crabs. Once their prey has ventured too close to the shark, the wobbegong opens its mouth and a huge influx of water sucks in the prey. The jaws snap closed in a fraction of a second and the fish is sucked down into its stomach (Parker, 2008). Wobbies are masters of the ambush!
While this video clip features the tasseled wobbegong rather than the ornate wobbegong, it beautifully demonstrates the hunting tactics that all species of wobbegongs are have perfected over millions of years of evolution.
Discovery [Discovery]. (10 July 2015). The Tasseled Wobbegong Shark Lures in Prey for Ambush [Video Clip]. Retrieved from https://www.youtube.com/watch?v=mbv2DhcKAh4
Length: About 5.5 feet (175 cm) long
Habitat: Coastal, coral/rocky reefs, intertidal, estuaries, bays, and seagrass flats
Depth: Shallow reefs and intertidals
Gestation: 10-11 months
Litter Range: Up to 12 pups 8 inches (20 cm) in length
Home Range: Tropical to warm temperate waters in the Western Pacific
Diet: Bottom fishes, invertebrates, shark and skate egg cases, crabs
IUCN Status: Least Concern
(Skomal, 2016; Huveneers, Pollard, Gordon, Flaherty, & Pogonoski, 2015; Parker, 2008; Tricas et al., 1997)
I hope you enjoyed this week’s featured species! Leave me a message and let me know what species you’d love to see featured! If you missed last week’s post, be sure to check out the the beautiful Giant Manta Rays!
Featured Image Source
Green, A. J. (Photographer) (n.d.). A Banded Wobbegong, Orectolobus ornatus – Great Barrier Reef, Queensland [Digital Image]. Retrieved from http://fishesofaustralia.net.au/home/species/1976
Angela, P., Angela, A., & Recchi, A. L. (1998). Sharks!: Predators of the sea. Philadelphia, PA: Courage.
Huveneers, C., Pollard, D.A., Gordon, I., Flaherty, A.A. & Pogonoski, J. 2015. Orectolobus ornatus. The IUCN Red List of Threatened Species 2015: e.T41838A68638906.
Parker, S. (2008). The encyclopedia of sharks (2nd ed.). Buffalo, NY: Firefly Books Ltd.
Skomal, G. (2016). The Shark Handbook: The Essential Guide for Understanding the Sharks of the World. (2nd ed.). Kennebunkport, ME: Cider Mill Press.
Tricas, T.C.; Deacon, K.; Last, P.; McCosker, J.E.; Walker, T.I.; Taylor, L. (1997). The Nature Company Guides: Sharks and Rays. (L. Taylor, Ed.). Hong Kong: The Nature Company, Time Life Books.