The rat is a medium-sized mammal that originated from Asia and Australia but are now found anywhere in the world. “True rats” are members of the genus Rattus, but other rodents are also referred to as rats and share many identical characteristics. They are commonly distinguished from mice by their size.
As stated in the Integrated Taxonomic Information System (ITIS) there are over 60 species of rat and they come in various sizes. They are commonly 5 inches (12 centimeters), or bigger, according to Encyclopedia Britannica. The biggest of all species is the Bosavi woolly rat, which was located in 2009 in the rainforest of Papua New Guinea. It is around the size of a cat — 32.2 inches (82 cm) from end to end and weighs around 3.3 lbs. (1.5 kilograms), as stated from CNN. One of the littlest of rats is Osgood’s Vietnamese rat. It is mostly 5 to 7 inches (12 to 17 cm) long.
According to the Australian Broadcasting Corp., males are named bucks; females are does. Infants are called pups. A group of them is termed a mischief.
These rodents are found all around the world. For example, rice-field rats are discovered in Southeast Asia, the Australian swamp rat is found in Eastern Australia, and the Norway rat, also named brown rats, is actually on every continent of the world except Antarctica, as reported by the Animal Diversity Web at the University of Michigan.
The brown and the house rat are the most typical rats in the world because they have taken boats to every country over the past several centuries. House rats commonly like warmer climates, while brown rats live in cool climates. They typically live in whatever place humans live. Many types also live in trees.
Generally, these rodents live to forage and mate. A lot of them are nocturnal, though the brown rat is often awake day or night.
Rats mostly band in groups called packs. New packs are formed when a male and female go off alone and nest in an area that doesn’t have a pack. Brown rats are commonly led by the largest male in the pack. Others may have a couple of dominant males or females in a pack.
They are omnivores like us, but many would choose meat when they can get it. House and brown rats mostly use humans for their primary food source. They will roam through trash or eat any food that is left exposed.
Rats have also been known to consume grain or kill insects, snails, fish, small birds, mammals and reptiles for food. Some, such as the Sulawesi white-tailed and Hoffman’s rat, prefer vegetarian foods fair such as seed and fruits, as stated in Encyclopedia Britannica.
Before their pups are born, they build nests from materials that can be gathered from the area, including branches, paper, trash and grass. These nests are ( for the most part ) built in crevices, in rotting trees or in buildings.
Rats, usually, are baby-making machines. Females can mate over 500 times in a six-hour period and brown rats can deliver up to 2,000 offspring in a year, according to Discover Magazine. Brown rats can deliver up to 22 young at once, though eight or nine is more the typical quantity. Tropical rats go only for one to six babies at once.
After the period of 21 to 26 days, pups that weigh only about 6 to 8 grams (.21 to .28 ounces) are born, as stated in the American Association for Rodents. When they get to the age of three months, the brown rat is ready to breed. Rats commonly live around two or three years. Most house rats ( 90 to 97 % ) die in their first year of life, as reported by the University of Michigan.
Here is the taxonomy according to ITIS:
- Kingdom: Animalia
- Subkingdom: Bilateria
- Infrakingdom: Deuterostomia
- Phylum: Chordata
- Subphylum: Vertebrata
- Infraphylum: Gnathostomata
- Superclass: Tetrapoda
- Class: Mammalia
- Subclass: Theria
- Infraclass: Eutheria
- Order: Rodentia
- Suborder: Myomorpha
- Superfamily: Muroidea
- Family: Muridae
- Subfamily: Murinae
- Genus: Rattus
The types include:
- Rattus argentiventer — Rice-field rat
- Rattus hoffmanni — Hoffmann’s Sulawesi rat
- Rattus lutreolus — Australian swamp rat
- Rattus norvegicus — Norway rat ( the brown rat )
- Rattus osgoodi — Osgood’s Vietnamese rat
- Rattus rattus — House rat, or black rat
- Rattus xanthurus — Northeastern Xanthurus rat, or Sulawesi white-tailed rat
The International Union for Conservation of Nature (IUCN) puts 16 rat species on its List of Threatened Species. They are treated threatened with extinction due to loss of habitat and have decline in their populations.
- Rattus elaphinus (Sula Archipelago)
- Rattus feliceus (Spiny Seram Island)
- Rattus jobiensis (Yapen)
- Rattus hoogerwerfi (Hoogerwerf’s Sumatran)
- Rattus palmarum (Zelebor’s Nicobar)
- Rattus richardsoni (Glacier)
- Rattus satarae (Sahyadris forest)
- Rattus stoicus (Andaman)
- Rattus xanthurus (Northeastern Xanthurus)
- Rattus burrus (Miller’s Nicobar)
- Rattus hainaldi (Hainald’s Flores Island)
- Rattus lugens (Mentawai Archipelago)
- Rattus montanus (Sri Lankan mountain)
- Rattus ranjiniae (Ranjini’s field)
- Rattus simalurensis (Simalur Archipelago)
- Rattus vandeuseni (Van Deusen’s)
Other facts and information
Brown and house rats have got some mammal, bird and reptile species extinct, primarily on oceanic islands, according to Encyclopedia Britannica. In addition to that they also spread diseases among people, including bubonic plague.
But, not all of them are bad. Brown rats are used in laboratories for research. The Foundation for Biomedical Research states that 95 percent of all lab animals are mice and rats.