You are likely quite familiar with the sound of birds singing. You might have also heard the sounds of frogs singing a chorus around a pond or lake. But did you know that some mice sing too? What is the reason behind this unusual behavior? [Read more…]
Blurry vision in humans often results in a prescription for glasses, contacts, or even surgery to restore a person’s vision to 20/20. For jumping spiders, however, blurry vision is an asset. Research by a team of scientists at Osaka City University in Japan indicates that the key to a jumping spiders leaping prowess is its unusual method of depth perception. [Read more…]
The cone snail is one of the slowest-moving carnivorous snails. But what it lacks in speed, it makes up for in potency of venom. In fact, a sting from the geographic cone snail, for which no antivenin exists, has resulted in several human deaths. For the most part, however, cone snails reserve their stings for victims that they can actually eat, such as mollusks, worms, or fish. [Read more…]
The mantis shrimp is neither a mantis nor a shrimp, but it got its name due to its resemblance to both of these creatures. The mantis shrimp is actually a marine crustacean that belongs to the order Stomatopoda. These unusual marine dwellers separated from other crustacean groups about 400 million years ago. Currently, scientists have identified over 350 different species of mantis shrimp. These shrimp are primarily found in tropical and subtropical waters, though some live in temperate ocean habitats.
There are two main types of mantis shrimps. The two types are distinguished by the appearance of their raptorial appendages, or raps. Spearers have sharp barbs on the tip of their rap, which they use to spear soft-bodied prey, such as shrimp or fish. Smashers have a club-like modification on their raptorial appendage, which lets them smash their shelled prey, such as clams and snails. Perhaps what makes the smashers club-like weapon most formidable is the speed at which it can be deployed. Scientists using super-high speed video cameras were able to calculate the speed at which a smasher mantis shrimp strikes its prey. So how fast is a mantis shrimp’s punch? At a speed of nearly 80 kilometers per hour (50 mph), a strike from a mantis shrimp counts as one of the fastest limb movements in the entire animal kingdom.
But their raptorial appendage weaponry is not the only strange thing about mantis shrimp. Mantis shrimp eyesight is also quite unusual. To begin with, their eyes are able to distinguish between 100,000 different colors–that is 10 times the amount that human eyes perceive. Why might mantis shrimp have the ability to perceive such a wide range of wavelengths? It turns out that a number of mantis shrimp species have fluorescent yellow markings on the scales of their antennae and carapace. Research published in January 2004 in the journal Science indicates that the fluorescent markings are part of a threat display directed toward males of the same species as well as potential predators.
According to research published in March 2008 in the journal Current Biology, one benefit of circular polarization vision is that it enhances contrast in murky conditions, such as the turbid waters that mantis shrimp inhabit, which lets the shrimp see better in their surroundings. In addition, research indicates that the males of some species of mantis shrimp have a patch on their bodies that reflects circular polarized light. Scientists hypothesize that these reflective patches may be used as a part of a sex-specific secret communication channel between mantis shrimp, since other marine animals cannot perceive CPL.
Recent research published in August 2011 in the journal Aquatic Biology indicates that mantis shrimp also communicate by rumbling. Vibrations within the mantis shrimps muscles are responsible for these low-frequency noises. Recordings made near the animals muddy underwater burrows indicate that the mantis shrimp use these noises as a way to establish and maintain territories. Since only males were observed making these noises, scientists think that the rumbling may also be used to attract female mates.
Though these strange underwater creatures have been around for 400 million years, much remains unknown about them, particularly since they spend most of their time in their undersea burrows. Many mantis shrimp species are also nocturnal, which makes tracking their behavior that much more difficult. However, from the data and observations that researchers have been able to gather thus far about mantis shrimp behavior and body composition, it seems these strange marine crustaceans are definitely worth the extra effort required to study them.
More to Explore
- Secrets of the Stomatopod
- Chesapeake Bay Field Guide: Mantis Shrimp
- TEDTalks: Sheila Patek Clocks the Fastest Animals (video)
- The Mantis Shrimp Has the Worlds Fastest Punch
- Mantis Shrimp versus Clam (video)
- New Form of Vision Discovered
- Shrimp Eyes Might Inspire New High-Def Devices
- Fluorescent Enhancement of Signaling in a Mantis Shrimp
- Mantis Shrimp: Ocean Floor Critters Communicate in Synchronized Rumbles
- Rumbling in the Benthos: Acoustic Ecology of the California Mantis Shrimp Hemisquilla californiensis (pdf)
The female deep sea anglerfish uses a bioluminescent lure that dangles over her head to attract prey. However, her lure isn’t just used to capture food to eat. Male anglerfish use the females light source to make sure shes a member of the same species before he latches onto her as a lifelong mate.
There are more than 200 species of anglerfish that live within the Atlantic and Arctic oceans. Though many live at depths of nearly 1000 meters beneath the oceans surface, a few species inhabit the shallow waters of tropical habitats.
Female and male anglerfish look quite different from one another. Only females have a lure above their heads. The lure is actually a portion of the females dorsal spine which glows a blue-green color due to the presence of bioluminescent bacteria. Because their rounded shape makes them poor swimmers, an anglerfish typically lies in wait for its prey, waving the lure back and forth slowly. In addition to its unusual headgear, the female also features a ferocious mouthful of sharp teeth that angle inward, which helps prevent prey from escaping once the food is in its mouth. The fish are also able to open their jaws wide enough to swallow prey twice their size, allowing them to make the most of each meal.
In comparison to females, male anglerfish are much smaller in size. In fact, one male anglerfish specimen holds the title as the worlds smallest vertebrate, measuring in at just 6.2 millimeters in length. As the male anglerfish matures, its digestive system begins to deteriorate, rendering it basically unable to get the nutrients it needs to live. To survive, the male anglerfish must find a mate. A pair of nostrils and a set of large eyes dominate a male anglerfishs face. It uses its nostrils to sniff out the scent of pheromones that announce the presence of nearby female anglerfish. It uses its large eyes to ensure that the anglerfish it sees is a member of the same species. Once it has found a mate, the male latches onto the females back, belly, or side by biting it with its own set of sharp teeth. Its at this point that things get really interesting.
Once the male bites the female, the male releases enzymes that cause its mouth to dissolve along with the females skin, which fuses the two together. Over time their bloodstream becomes one, and the male loses his eyes along with all other internal organs except for its testes. The female is now for all intents and purposes a hermaphrodite, meaning it can self-fertilize. A female may have more than six males on its body at one time. However, some females live their entire lives–which may span between 25 and 30 years–without ever encountering a male.
When the female is ready to reproduce, it lays eggs in a huge swath one meter wide by nine meters long. This sheet of eggs floats freely in the oceans waters. Larvae hatch from the eggs and feed on plankton at the waters surface before returning to the oceans depths as they mature, beginning their unusual deep-sea life cycle once again.