Shrew

Shrews are creatures of the kingdom Carpozoa descended from the Shrew Lizard. Shrews in general bear several similarities to mammals on Earth. They produce milk for their young just like mammals, and most species have a marsupium in which they raise their young. Most shrews, like the majority of Carpozoa, have six eyes, and all the shrews have at least a rudimentary sense of hearing inherited from the Shrew Lizard. All extant species are warm-blooded, though they were ancestrally cold-blooded--endothermy evolved completely independently in furred shrews and bubbleskins.

There are two major branches of Shrew, the furred shrews and the blood shrews. Furred shrews retain a fairly mammalian appearance, while blood shrews took on more varied appearances. Today, furred shrews are only represented by descendants of the Marine Tamow and blood shrews are only represented by the decidedly not-mammal-like Bubbleskins.

Anatomy
Shrews typically have four limbs. Though they evolved from pentapeds, the tail remains flexible and tail-like, as it was in their direct ancestors. They typically have heterodont teeth, including pointed canine teeth. Most shrews have a pouch, generally located on the belly or between the legs, which is used to incubate their altricial young. They produce milk inside the pouch, which their offspring drink for nourishment. As carpozoans, they typically have 6 eyes, and their nostrils are located on their faces, usually at or near the tip of the snout. All modern shrews are warm-blooded, though naked cold-blooded shrews existed in the past.

Integument
The two major extant lineages of shrew have very different approaches to insulation.

Furred shrews, as their name suggests, have fur. This is similar to mammalian fur in that it is filamentous, made of keratin, and has a follicle. It provides insulation in a manner similar to fur, feathers, and setae on Earth.

Bubbleskins have a unique approach to insulation. Rather than fur, each of their keratinous scales has a hollow air-filled core. Though anatomically very different, they work on a similar principle--heat stays inside the body because it has difficulty being transferred through the bubbly scales.

Behavior
As there are many types of shrew, their behavior is extremely varied. All shrews have parental care.

Intelligence
Shrews have rarely developed high intelligence. Dromaeocanid shrews developed ape-like intelligence, but they were wiped out by the Shrew Plague and never produced a sapient species.

The Tamjack and its descendants seem to show higher intelligence than their relatives. Most notably among them, the Seashrog developed high ape-like intelligence, a first since the extinction of the dromaeocanids.

Breathing and Blood
Shrews have red, iron-based blood. Their have lungs and require air to breathe.

Diet & Energy
Shrews have varied diets, with many being herbivores or omnivores. Blood shrews, including bubbleskins, were ancestrally hemophagus, as their name suggests.

Evolution
Shrews first evolved in Generation 64. The first appearance of fur in what would become the furred shrews was in Generation 67. Blood shrews first evolved in Generation 69, and the first Bubbleskin appeared in Generation 138.



Extinction Events and Radiations
Though they remain extant to this day, shrews are no stranger to extinction events, often being whittled down to just a few species in major ones.

Most of the shrews, even the Shrew Lizard, were wiped out by a deadly plague in generation 95. This plague was spread by one of their parasitic members, the Death Soriparasite. All extant shrews at the time went extinct except for the Bearded Shrew, the River Shrew, the Soriparasite, and the Night Glider. The bearded shrew, the soriparasite, and all of their respective descendants would soon also go extinct due to the gamma-ray burst, which ultimately left only the Beach Shrotter, the Cave Night Glider, and the Velishroot. These would go on to radiate into a diverse variety of forms.

When the ice age struck, all Shrews went extinct except for the Whiskerpick, the Bubbleskin, and their respective descendants. While Bubbleskins continued to diversify and thrive across different parts of the world, especially Drake and Vivus, when the ice age ended the surviving furred shrews were restricted mostly to Jaydoh. Two small populations of Iciclebacks actually survived in Barlowe, but they became extinct from habitat loss without producing descendants.

As an island continent, Jaydoh developed a unique assemblage of creatures, including megafaunal shrews. However, as the sea levels rose, Jaydoh eventually sank. When this occurred, all furred shrews apart from descendants of the Marine Tamow became extinct. This leaves a subgroup of Tams as the furred shrew crown group, and they have since diversified into many new forms across the globe. As of Week 26, at least one species of Shrew is present on each landmass.

Locomotion
Among extant shrews, most furred shrews are quadrupeds while most bubbleskins are bipeds. In general, similar to Terran mammals, Shrew locomotion is hind limb-powered.

Among aquatic Shrews, if they propel themselves with their tail they typically use an up-down motion. A notable exception is the shrotters, which use a left-right undulation like a Terran fish instead.

Reproduction
Shrews ancestrally brooded larval, fetal young inside a pouch and fed them milk, much like a Terran marsupial. A handful of species have developed a placenta.

Senses
Shrews ancestrally possess the ability to hear. Furred shrews have pinnae. Several blood shrews evolved more advanced ears independently, but the extant bubbleskins lack any external ears and must hear using their jaw bones like the original Shrew Lizard did.

Shrews have nostrils on the end of their nose which allows them to smell. Like most Carpozoans, they have 6 eyes.

Size
Shrews come in many sizes. They are generally small, but megafaunal Shrews are possible and have appeared many times throughout Sagan IV's history.