Blue Whale in Costa Rica
October 30th, 2012
Common Name: Spanish Dancer
Scientific Name: Hexabranchus sanguineus
Max. Length: 60 centimeters
Ave. Length: 20-30 centimeters
Diet: Sponges and Tunicates
Frequency: Abundant but threatened due to rise in seawater temperature
Range: Pacific and Atlantic Coast
First of all, let us make this clear that we are not talking about that lady in red who dances to the tune of flamenco. What we are talking about is the largest species of sea slugs or nudibranch. This blood-colored marine gastropod can grow up to 60 centimeters, but its average length is somewhere in between 20 to 30 centimeters long.
A Swimming Spanish Dancer. Photo courtesy from National Geographic.
Aside from its size, you can easily identify a Spanish Dancer through its behavior and color patterns. The body of this so-called giant sea slug is generally orange-red and speckled with several small white dots. In juveniles, the body is colored white to yellow with purple spots around the body. In a normal situation, the Spanish Dancers’ soft and flattened body can be seen gently crawling in the bottom of the seafloor while its mantle is curled inwards. But if the animal is disturbed or threatened, the edges of its mantle are unfold giving it the ability to swim away through the contraction and undulation of its body. While most of us are amazed when we see a Spanish Dancer swimming, now we know that the animal is not displaying its amazing talents, rather it shows that it is being threatened and distress. So, the next time you see a swimming Spanish Dancer, give it a distance when observing and please turn off those strobes if you are doing underwater photography as the flashy lights can further distress the animal. Use continuous light instead, like the ones from your underwater torch or flashlight.
Photo courtesy from leisurepro.com
Generally, in the wild, camouflage is the best defense for survival where a brightly colored body can easily attract a predator. But this is not the case for a Spanish Dancer and the rest of the nudibranch family even if they are moving very slow. Their brightly colored body is a sign for predators to keep off as they contain toxins derived from a species of Halichondria sponge which is part of their diet.
The symbiotic relationship of a Spanish Dancer and an Emperor Shrimp. Photo courtesy from dfiles.
This giant nudibranch can be found throughout the tropical and subtropical regions of the Indo-Pacific Ocean. While hiding away from sunlight, Spanish Dancers lives in cracks and crevices along with sponges and tunicates which are their main diet. If you take a closer look at the body, you can usually see a small Emperor Shrimp (Periclimenes imperator) which lives symbiotically with the Spanish dancer.
An egg of a Spanish Dancer. Photo courtesy from ferrebeekeeper.
You can occasionally find Spanish Dancers, along with other species of nudibranch, in Costa Rica particularly in the huge tidal pools near Playa Hermosa. Their presence is recorded to exist along the Pacific Coast of Central America. In some areas, the eggs of Spanish Dancers, which looks like coiled rosettes, have been observed to be laid and deposited in rocks and coral rubbles. They have been known to be preyed upon by fishes particularly Moon Wrasse (Thalassoma lunare) and the white-spotted hermit crab (Dardanus megistos) where both can tolerate the toxins inside the Spanish Dancers’ body.
Wikipedia: https://en.wikipedia.org/wiki/Spanish_dancer
Sealifebase: http://www.sealifebase.org/summary/Hexabranchus-sanguineus.html
video courtesy from Scubazaru