#Species: acouchy

[fenrislorsrai]

Acouchi by Smithsonian's National Zoo Via Flickr: Photo Credit: Smithsonian's National Zoo With temperatures soaring, the Smithsonian’s National Zoo continues to take good care of its creatures—human and non-human alike! Here’s what we do for our animals in this heat: •Most of the animals that can go outside are offered a choice year round—to go outside or to stay in their indoor exhibit. Most indoor exhibits are cooled with AC in the summer and warmed with heat in the winter. •Giant pandas have air-conditioned and radiant water-chilled grottos. They have AC indoors. They’re not huge fans of heat, so on hot days they mostly stay inside. •Many animals are offered fruitsicles as enrichment, which can be particularly refreshing this time of year. Fruitsicles are popsicles—they are usually diluted fruit juice frozen with cut-up chunks of fresh fruit in them. Gorillas, elephants and other bears enjoy these treats, too. (Note that these aren’t just a summertime treat! They receive them year-round.) •Some animals have the option of taking a dip in their outdoor pools: Andean bears, pandas, lions, tigers, anteaters and otters. Others are acclimated to this weather. Our visitors have a number of options for staying cool: •Water fountains are available around the park. •They can enjoy a number of “misters” around the Zoo. •The Zoo sells a variety of ice cream and frozen treats, along with cold beverages and bottled water. •All of our animal houses are air conditioned.

[bestanimal]

Round 3 - Mammalia - Rodentia

(Sources - 1, 2, 3, 4)

Our next and last order of the Glires clade is the Rodentia. Rodentia is the largest order of mammals, with about 40% of mammal species being rodents. Rodentia is comprised of the families… *deep breath*… Anomaluridae (“scaly-tailed squirrels”), Zenkerellidae (“Cameroon Scaly-tail”), Pedetidae (“springhares”), Castoridae (“beavers”), Geomyidae (“pocket gophers”), Heteromyidae (“kangaroo rats/mice” and “pocket mice”), Ctenodactylidae (“gundis”), Diatomyidae (“Laotian Rock Rat”), Bathyergidae (“African mole-rats”), Heterocephalidae (“Naked Mole-rat”), Hystricidae (“old world porcupines”), Petromuridae (“Dassie Rat”), Thryonomyidae (“cane rats”), Chinchillidae (“chinchillas” and “viscachas”), Dinomyidae (“Pacarana”), Caviidae (“cavies”), Dasyproctidae (“agoutis” and “acouchis”), Cuniculidae (“pacas”), Abrocomidae (“chinchilla rats”), Ctenomyidae (“tuco-tucos”), Echimyidae (“Nutria”, “spiny rats”, and “hutias”), Octodontidae (“degus” and kin), Erethizontidae (“new world porcupines”), Dipodidae (“jerboas”), Sminthidae (“birch mice”), Zapodidae (“jumping mice”), Calomyscidae (“mouse-like hamsters”), Cricetidae (“hamsters”, “voles”, “lemmings”, “muskrats”, and “new world rats/mice”), Muridae (“true rats/mice” and “gerbils”), Nesomyidae (“Malagasy rats/mice”, “climbing mice”, “African rock mice”, “swamp mice”, “pouched rats”, and “White-tailed Rat), Platacanthomyidae (“spiny dormice” and “Chinese pygmy dormice”), Spalacidae (“mole-rats”, “bamboo rats”, and “zokors”), Aplodontiidae (“Mountain Beaver”), Gliridae (“dormice”), and Sciuridae (“squirrels”).

The distinguishing feature of rodents is their pairs of continuously growing, razor-sharp, open-rooted incisor teeth. These incisors have thick layers of enamel on the front and little enamel on the back. Because they do not stop growing, the animal must continue to wear them down so that they do not reach and pierce the skull. Some rodents have elastic cheeks or even cheek pouches for storing food. They usually have flexible fore limbs with five digits, including an opposable thumb, while the hind limbs can have three to five digits. The majority of species are plantigrade, walking on both the palms and soles of their feet, and have claw-like nails. Many rodents have well-developed senses of smell, hearing, and vision. Nocturnal species often have enlarged eyes and some are sensitive to ultraviolet light. Many species have long, sensitive whiskers for touch. Some have prehensile tails, some have vestigial tails or no tails at all. Rodents are highly diverse, having evolved to fill a large variety of niches and filling almost every land-based habitat on Earth. There are terrestrial, fossorial, arboreal, semi-aquatic, herbivorous, omnivorous, insectivorous, and carnivorous rodents. Rodent species use a wide variety of methods of locomotion including quadrupedal walking, running, burrowing, climbing, bipedal hopping, swimming, and even gliding. Many rodents have advanced cognitive abilities, and display advanced feats of memory and intelligence.

Sexual dimorphism occurs in many rodent species. In some rodents, males are larger than females, while in others the reverse is true. Rodents exhibit a wide range of types of social behavior ranging from the caste system of the Naked Mole-rat (Heterocephalus glaber), the extensive "towns" of the colonial prairie dogs (genus Cynomys), through family groups to the independent, solitary life of the edible dormice (genus Glis). Beavers (genus Castor) live in extended family units typically with a pair of adults, and both their recent kits and older young. Brown Rats (Rattus norvegicus) usually live in small colonies with up to six females sharing a burrow and one male defending the territory around the burrow. The Prairie Vole (Microtus ochrogaster) is monogamous and forms a lifelong pair bond. Female rodents tend to play an active role in choosing their mates. Factors that contribute to female preference may include the size, dominance and spatial ability of the male. Rodents may be born either altricial (blind, hairless and relatively underdeveloped) or precocial (mostly furred, eyes open and fairly developed) depending on the species. In many social species, young may be cared for by individuals other than their parents, a practice known as alloparenting or cooperative breeding.

According to the fossil record, Rodentia arose in the Paleocene, probably in Asia, shortly after the extinction of the non-avian dinosaurs some 66 million years ago. Some molecular clock data suggest Rodentia had already appeared by the Late Cretaceous, although other molecular divergence estimations are in agreement with the fossil record.

Propaganda under the cut:

Many rodents are “ecosystem engineers”: species which have a huge impact on their habitat. Ecosystem engineers are important for maintaining the health and stability of the environment they are living in. Beavers (genus Castor) (see gif above) are often used as the prototypical ecosystem engineer example, because of the impact their dams have on channel flow, geomorphology, and ecology. Beavers can create entire wetlands, habitat which is then used by millions of other species. Ground squirrels such as Groundhogs (Marmota monax) and prairie dogs (genus Cynomys) perform substantial modifications by burrowing and turning soil. They are able to influence soils and vegetation of the landscape while also providing burrows that are used by other species. Many tree squirrels bury nuts over a widespread area (scatterhoarding), and often forget them, resulting in entire new generations of forest diversity being planted.

Two distinct, unrelated groups of rodents evolved the ability to glide with a membrane between their front and hind legs. These are the Anomalurids (“scaly-tailed squirrels”) and the Flying Squirrels (Sciurid squirrels of the tribe Pteromyini) (image 4). Sciurids are most closely related to the Mountain Beaver (Aplodontia rufa) and dormice (family Gliridae). Anomalures are most closely related to springhares (family Pedetidae) and the Cameroon Scaly-tail (Zenkerella insignis). The only other mammals to evolve this gliding ability are the colugos and the some possums. This is an example of convergent evolution, where arboreal, climbing mammals found a way to more easily travel from tree to tree.

Springhares (genus Pedetes) (image 1) sleep standing up, with their head and forelimbs bent down in between their hindlegs, and their tail wrapped around their feet.

Beavers hold territories and mark them using scent mounds made of mud, debris, and a vanilla-like musk called castoreum—a liquid substance excreted through the beaver's urethra-based castor sacs. Castoreum was historically used for a variety of medical purposes; Pliny the Elder promoted it as a treatment for stomach problems, flatulence, seizures, sciatica, vertigo, epilepsy, hiccups, toothaches, and envenomations. By the early 20th century, castoreum began appearing in some foods to add a vanilla-raspberry flavor. But its use had fallen by 1987, when the U.S. consumed about 250 pounds of castoreum per year. Since then, its use has decreased significantly, now mostly found in niche foods such as Swedish liquor and some perfumes.

The Eurasian Beaver (Castor fiber) was hunted almost to extinction for both its water-resistant fur and castoreum by the early 20th century. Beaver hats were fashionable across much of Europe between 1550 and 1850 because the soft yet resilient material could be easily combed to make a variety of hat shapes (including the familiar top hat). Demand was so high, that when Eurasian Beavers could no longer be found, the gaze of European fashion turned to the New World and the North American Beaver (Castor canadensis), which was then also hunted to near-extinction. A shift in fashion trends toward silk hats may have been the only thing that saved these two species. Today, after considerable conservation efforts and reintroductions, both beaver species have recovered from this severe over-exploitation.

Gundis (family Ctenodactylidae) can climb up almost vertical surfaces.

The Naked Mole-rat (Heterocephalus glaber) is highly unique for many reasons, one being that it is the only mammal with an almost entirely ectothermic (cold-blooded) form of body temperature regulation. They also lack pain sensitivity in their skin, have very low metabolic and respiratory rates, are resistant to cancer and oxygen deprivation, and can live over 37 years. Naked Mole-rats are also eusocial, forming a complex social structure which includes a reproductive division of labor, separation of reproductive and non-reproductive castes, and cooperative care of young. The only other eusocial mammal is the Damaraland Mole-rat (Fukomys damarensis).

Another example of convergent evolution involves spines. Both Old World Porcupines (family Hystricidae) and New World Porcupines (family Erethizontidae) (image 2), as well as spiny rats (genus Tokudaia) and spiny mice (subfamily Deomyinae), are not particularly closely related to each other. We also see spines in the even more distantly related hedgehogs, tenrecs, and echidnas. Many groups of small animals around the world seemed to have turned their mammalian fur into this unique defense mechanism.

Chinchillas (genus Chinchilla) have the densest fur of all living terrestrial mammals, with around 20,000 hairs per square centimeter and 50 hairs growing from each follicle. This gives them some of the softest fur in the world. Unfortunately, this has made their fur highly desirable for the fur trade, and both species of chinchilla are now endangered. A single, full-length coat made from chinchilla fur may require as many as 150 animals. Domestic Chinchillas descended from the Long-tailed Chinchilla (Chinchilla lanigera) are sometimes kept as pets, and are also bred and raised on fur farms.

The largest rodent ever known to exist was the the extinct, bison-sized Josephoartigasia monesi. Today, its only living relative is the much smaller Pacarana (Dinomys branickii).

The Greater Capybara (Hydrochoerus hydrochaeris) is the largest living rodent, growing to 106 to 134 cm (3.5 to 4.4 ft) long, standing 50 to 62 cm (1.7 to 2 ft) tall at the withers, and typically weighing 35 to 66 kg (77 to 146 lb). Capybaras are highly social, and semi-aquatic, and can hold their breath underwater for up to five minutes at a time.

The Domestic Guinea Pig (Cavia porcellus) was domesticated from the wild Montane Guinea Pig (Cavia tschudii) as early as 5,000 BC by indigenous peoples in the Andean region of South America. Originally bred for its meat, the Domestic Guinea Pig is bred today for scientific research, for various color and coat types in shows, and as a pet. Their docile nature, friendly responsiveness to handling and feeding, and the relative ease of caring for them have made Guinea Pigs one of the most popular pet rodents.

The agoutis (family Dasyproctidae) are some of the most gracile rodent species, having an almost antelope or deer-like appearance, complete with hoof-like toes.

The beautiful Norway Lemming (Lemmus lemmus) is known for being one of the most aggressive rodents, despite its small size. When cornered by predators (including humans), they have been known to go on the attack. This is thought to be an attempt to deter predation by using their bold coloration, loud calls, and aggressive behavior to advertise their ability to harm small predators.

The Maned Rat (Lophiomys imhausi) is the only known poisonous rodent. Its long hairs are spongy, fibrous, and absorbent with a honeycomb structure. The rat is known to deliberately smear these hairs with poison from the bark of the Poison Arrow Tree (Acokanthera schimperi), on which it chews. Its mane of hairs absorbs the poison, thus creating a defense mechanism that can sicken or even kill predators which attempt to bite it.

The Rakali (Hydromys chrysogaster) is a semi-aquatic rat native to Australia, and fills a similar niche to river otters, hunting a variety of aquatic animals including fish, crustaceans, shellfish, eggs, mammals, frogs, and small reptiles.

The Brown Rat (Rattus norvegicus) is one of the most successful rodents in the world, living wherever humans live. They have adapted to survive well in urban environments, a genius survival strategy in an increasingly human world.

Domestic Rats are also called Fancy Rats (Rattus norvegicus domestica), and were bred from Brown Rats in 18th century Europe, when rat-catchers who caught and bred rats for rat-baiting noticed that some of their rats were prettier and more docile than the others. These rats were dressed up in ribbons and sold as pets. It was said that people who kept pet rats were struck with “rat fancy.”

Brown (and by extension Fancy) Rats are highly social and groom each other, sleep together in “piles”, play fight, emit ultrasonic “giggles” when excited, and show empathy to both their fellow rats and their bonded humans. In laboratory tests they have been shown to have intelligence levels rivaling that of primates, remembering complex mazes months after completing them, problem-solving, using tools, learning by watching other rats, planning ahead, and recognizing when they know something vs when they don’t. In laboratories and in peoples’ homes, rats can quickly be taught to come when called, play fetch, do agility courses, sort recycling and trash, and drive cars.

Fancy Rats are the best “exotic” pets and I currently have 9 of them. Their names are Magpie, Blue Jay, Raven, Versace, Gucci, Prada, Chanel, Nordstrom, and Porcini. I don’t have a photo of all of them together because have you ever tried to get a group photo of 9 rats? If Rodentia makes it to Round 3 I will Try.

As an adaptation to life in the desert, Australian Hopping Mice (genus Notomys) can concentrate their urine to as high as 10,000 mOsm/L (10-20 times higher than a human).

The Earless Water Rat (Crossomys moncktoni) is the most aquatically adapted rodent in the world. It has long hindfeet with completely webbed toes, strongly reduced forelegs, absent or invisible ears, very small eyes, and soft, waterproof fur. It resembles the Elegant Water Shrew (Nectogale elegans), another example of convergent evolution.

The Fancy Mouse is the domesticated form of the House Mouse (Mus musculus), which was domesticated in China sometime before 1,100 B.C. Today, Fancy Mice are available in dozens of different colors, markings, and coat types, and are popular for their small size and relatively inexpensive care.

Southern Giant Pouched Rats (Cricetomys ansorgei) are trained by the Tanzanian group APOPO ("Anti-Personnel Landmines Removal Product Development" in English) to sniff out land mines and detect tuberculosis with their highly developed sense of smell. The trained pouched rats are called HeroRATS. In 2020, a HeroRAT named Magawa received a People's Dispensary for Sick Animals Gold Medal, the animal equivalent of the George Cross, becoming the first rat to receive the award since the charity began honouring animals in 2003. Before retiring in 2021, Magawa detected 71 landmines and 38 items of unexploded ordnance, clearing over 2,421,880 sq ft (225,000 m2) of land in Cambodia during his 5-year career, preventing many deaths and injuries. Magawa died from natural causes at the age of 8 in 2022.

Prairie dogs (genus Cynomys) have a highly advanced language, with their alarm calls conveying information about not only the type of predator that’s been sighted, but also how big it is and how fast it’s approaching. Their calls contain information on whether a dog is a coyote, wolf, or domestic dog, with the colony changing their response depending on the predator. Their alarm calls even have language for the researchers studying them, and will change depending on the height and clothing color of the observing human.

168 species of rodent in 126 genera warrant conservation attention, but getting the public, and even scientists, to appreciate rodents is often an uphill battle, as many people associate rodents with the most familiar Brown Rats and House Mice. Since 76% of rodent genera contain only one species, much phylogenetic diversity could be lost with a comparatively small number of extinctions.