DIVE DRY WITH DR. BILL #848: GUARDIAN OF THE BURROW
I was diving near Hen Rock several years ago when I encountered a beautiful sight. No, it wasn't the mermaid of my dreams. It was a California mantis shrimp (Hemisquilla californiensis) outside its burrow. Usually when I encounter them, they are inside the burrow and barely visible. Occasionally I find them with their upper body sticking out, looking for danger. However, this one stayed outside its burrow racing around for the entire 45 minutes of my dive.
Mantis shrimp are not closely related to the shrimp we find in shrimp cocktails (although some cultures do eat them). They are in the arthropod class Malacostraca which includes shrimp, lobster and crabs. However, they belong to the taxonomic order Stomatopoda which is believed to have branched off some 400 million years ago. And just to clarify they are not related to the character Mantis in "Guardians of the Galaxy."
Individuals may exceed a foot in length. They are generally tan to dull orange in color. The legs are blue and the tail is yellow. Their powerful claws are also yellow.
Their preferred habitat is over soft substrate like sand or mud down to depths of about 160 feet. Stable habitats with little disturbance from storms are desired. The waters off Hen Rock and White's Landing on Catalina are perfect for them. The geographic range extends from Pt. Conception to Panama. They dig their deep burrows in the substrate and often line the entrance holes with shells or rocks. Although I have not observed this, apparently they plug the entrance at night and during the middle of the day.
This mantis shrimp comes out after dawn and in late afternoon. They use their powerful claws to stun or kill molluscs, crustaceans and worms. In some species the claw can also pose a serious problem for underwater imagers. They can crack the glass port in underwater housings with it. Fortunately I have acrylic in mine, although none of our local species have attacked it.
In my research for this column, I found several scientific studies on the acoustic (sound) behavior of our mantis shrimp. Apparently they use low frequency sounds produced by muscles to communicate with other mantis shrimp in the neighborhood. Sound production peaks when they are out in the open and is more subdued when they are in their burrows at night and midday.
The sexes are separate in mantis shrimp and they reportedly pair off for life. However during much of the time they live separately and only come together when it's time to do "the wild thing." I haven't read anything about their mating rituals. Females are said to brood as many as 50,000 eggs. Upon hatching, they enter the plankton and drift for about 90 days before settling down.
© 2020 Dr. Bill Bushing. For the entire archived set of nearly 850 "Dive Dry" columns, visit my website Star Thrower Educational Multimedia (S.T.E.M.) Home Page
Image caption: Our local mantis shrimp in the open; peeking out of and in burrow; peacock mantis shrimp from Philippines and image showing claws (courtesy of the Australia Museum).
I was diving near Hen Rock several years ago when I encountered a beautiful sight. No, it wasn't the mermaid of my dreams. It was a California mantis shrimp (Hemisquilla californiensis) outside its burrow. Usually when I encounter them, they are inside the burrow and barely visible. Occasionally I find them with their upper body sticking out, looking for danger. However, this one stayed outside its burrow racing around for the entire 45 minutes of my dive.
Mantis shrimp are not closely related to the shrimp we find in shrimp cocktails (although some cultures do eat them). They are in the arthropod class Malacostraca which includes shrimp, lobster and crabs. However, they belong to the taxonomic order Stomatopoda which is believed to have branched off some 400 million years ago. And just to clarify they are not related to the character Mantis in "Guardians of the Galaxy."
Individuals may exceed a foot in length. They are generally tan to dull orange in color. The legs are blue and the tail is yellow. Their powerful claws are also yellow.
Their preferred habitat is over soft substrate like sand or mud down to depths of about 160 feet. Stable habitats with little disturbance from storms are desired. The waters off Hen Rock and White's Landing on Catalina are perfect for them. The geographic range extends from Pt. Conception to Panama. They dig their deep burrows in the substrate and often line the entrance holes with shells or rocks. Although I have not observed this, apparently they plug the entrance at night and during the middle of the day.
This mantis shrimp comes out after dawn and in late afternoon. They use their powerful claws to stun or kill molluscs, crustaceans and worms. In some species the claw can also pose a serious problem for underwater imagers. They can crack the glass port in underwater housings with it. Fortunately I have acrylic in mine, although none of our local species have attacked it.
In my research for this column, I found several scientific studies on the acoustic (sound) behavior of our mantis shrimp. Apparently they use low frequency sounds produced by muscles to communicate with other mantis shrimp in the neighborhood. Sound production peaks when they are out in the open and is more subdued when they are in their burrows at night and midday.
The sexes are separate in mantis shrimp and they reportedly pair off for life. However during much of the time they live separately and only come together when it's time to do "the wild thing." I haven't read anything about their mating rituals. Females are said to brood as many as 50,000 eggs. Upon hatching, they enter the plankton and drift for about 90 days before settling down.
© 2020 Dr. Bill Bushing. For the entire archived set of nearly 850 "Dive Dry" columns, visit my website Star Thrower Educational Multimedia (S.T.E.M.) Home Page
Image caption: Our local mantis shrimp in the open; peeking out of and in burrow; peacock mantis shrimp from Philippines and image showing claws (courtesy of the Australia Museum).
