Sea Squirt

Photo courtesy of AES Brittany

Hello Explorers! It's time for the Critter of the Week! Now, I have noticed there is a slight biased toward the recognizable critters thus far.
So, this week, it is time to bring you all something that may blow your mind! Instead of ju...st one critter, this name refers to a phylogenetic class that includes over 2300 species! I present, the humble sea squirt. Yes, that's right, the Sea Squirt. "Sea Squirt" is a common name that refers to the class Ascidiacea, which belongs to the subphylum tunicata, otherwise known as the tunicates.
Sea squirts are filter-feeding marine invertebrates that basically look like small sacs. As adults, they stick to a rock and prefer to remain attached the rest of their lives. The reason these animals are called sea squirts is because on the upper part of these sac like animals are two siphons. If one of these animals happen to be removed from the water, it will squirt water violently from these siphons. At first glance, these animals seem to be simplistic, perhaps pretty to look at, but nothing too special. However, there is something very special about sea squirts and the rest of the tunicates...
In the phylogenetic tree, which is the term applied to tracing the evolutionary relations of life (Kingdom, phylum, class, order, family, genus, species), tunicates and "vertebrata" (which include fish, amphibians, reptiles, birds and mammals) are sister subphylum. This means that tunicata and vertebrata shared a common ancestor from which the two subphyla split. Not only that, but Tunicates are closer related to vertebrata than to any invertebrate group. So think about that next time you see a sea squirt, and be sure to read more about them here:

http://en.wikipedia.org/wiki/Ascidiacea

Beluga

Photo courtesy of Stan Shebs

Hello Explorers! It's time for the critter of the week! In honor of the new baby at the Georgia Aquarium, our featured critter is the beluga whale! Beluga whales are the true white whales of the north. The white color helps to camoflaug...e them among the ice flows. Baby belugas, called calves, are born grey so they can hide in their mother's shadow. Belugas do not have a true dorsal fin, which is a good thing since belugas travel under the ice, and a dorsal fin would just scrape or bump against the ice. Instead they have a dorsal ridge on their back. These whales are known as the canaries of the deep, due to their different high pitched vocalizations. Belugas are very talkative. Since these whales live in the northern oceans of the world, they have a lot of fat, called blubber. One unique feature about the beluga is that, unlike other whales and dolphins, the neck vertebrae are not fused together, which allows for the beluga to turn its head side to side. 

Read more about this sea canary here:

http://en.wikipedia.org/wiki/Beluga_whale
 

Giant Pacific Octopus

Photo courtesy of NOAA/ R. N. Lea

Hey Explorers! Time for the Critter of the Week! This week, in honor of Mother's Day, we are spotlighting a very dedicated mother in the aquatic world: the Giant Pacific Octopus. The Giant Pacific Octopus, a type of cephalopod (which inc...ludes octopus, squid, cuttlefish, and nautilus) is the largest species of octopus in the world as well as the longest living octopus. However, they only live four years. Generally, after they breed, both male and female GPOs die shortly after. However, female GPOs actually live long enough to care for and protect the eggs that they lay, not leaving the nest to even eat! These mothers sacrifice their lives for their offspring. Go give your own mom a hug for the dedication she shows everyday to you!

You can read more about the Giant Pacific Octopus below:

http://animals.nationalgeographic.com/animals/invertebrates/giant-pacific-octopus/

Spiny Lobster

Photo courtesy of AESBrittany

G'day Explorers!
It's time for the Creature of the Week! This week, our critter is the spiny lobster! Now, the spiny lobster is not a true lobster. In fact, for those of you familiar with taxonomy, true lobsters and spiny lobsters share ...the same order (Decapoda), but then split into different Infraorders. For those of you who are not familiar with taxonomy, slipper lobsters are different from true lobsters in that they don't have claws (also known as chelae) on their front pairs of legs, they have long antennae covered in spines, and they have a unique larval stage. A recent discovery found something very unique about spiny lobsters: that in addition to being able to navigate using smells and tastes in the water, they can also navigate using the magnetic field of the Earth! Talk about sensitivity!
Read more about this cool invertebrate:

http://en.wikipedia.org/wiki/Spiny_lobster