Wild Rats vs Pet Rats – How Do They Differ?

If you’ve ever seen a wild rat, you might find it hard to reconcile that picture with the image of a cute pet rat riding on their owner’s shoulder.

Have you ever wondered if wild rats and pet rats are the same? And if not, how do they differ?

While pet rats are direct descendants of wild rats, they have changed a lot through the process of domestication. They now have distinct physical features and behavioral traits set them apart from their wild counterparts.

If you’d like to discover the main differences between wild and pet rats, read on to find out!

Pet Rats vs Wild Rats

Are Pet Rats and Wild Rats the Same?

There are many different species of wild rat. The one we usually talk about when referring to “wild rats” is the Norway rat or brown rat (Rattus norvegicus)1.

Norway rats can be found all over the world in a large variety of habitats, but they often stay close to human settlements. They are generally considered pests, as they can get into food supplies and spread diseases2.

The Norway rat was first domesticated for research purposes over 170 years ago, and our pet rats are descendants of these laboratory rats (sometimes also called fancy rats)3.

Black Rats at Karni Mata Temple India
Black Rats at Karni Mata Temple India. Credit: Image by Simon from Pixabay

Another common breed of wild rat is the black rat or ship rat (Rattus rattus). It is a bit smaller than the Norway rat and has a pointed nose and large ears. Black rats tend to be shyer than brown rats and are almost impossible to domesticate – they do not thrive in captivity.

Most of what we know about pet rats is derived from research performed on their laboratory counterparts. In the beginning of the 20th century, researchers already started to notice that domesticated rats differ from wild rats in certain physical traits as well as in their behaviour4.

What Are the Physical Differences Between Wild Rats and Pet Rats?

Keeping rats as pets
Fancy Rats

At first glance, you may notice that domesticated rats are smaller than their wild cousins5 (however, this might not be very noticeable as, sadly, most pet rats are overweight). However, pet rats reach their reproductive maturity sooner and have bigger litters5,6.

Another striking difference is the color: You will see mostly black, grey or brown wild rats (the latter is called “agouti”); whereas pet rats come in a huge variety of colors and patterns. Rat breeders have also created special varieties such as hairless rats, rex rats (with curly fur and curled whiskers) or dumbo rats (with their characteristically large ears).

dumbo-rats
Dumbo Rats

Pet rats and laboratory rats are sadly prone to developing tumors, and some speculate that this is due to inbreeding. However, it’s hard to say whether wild rats suffer from the same health issue, as they generally don’t live long enough to develop tumors. In fact, wild rats have a life expectancy of only about one year7, whereas pet rats can live up to two or three years with appropriate care.

The physical differences between wild and pet rats are not all obvious at a glance, though – they even have different anatomical brain structures8. Researchers think that this enables domesticated rats to learn more quickly than their wild ancestors. Let’s find out what other behavioral differences exist between wild rats and pet rats!

What Are the Behavioral Differences Between Wild Rats and Pet Rats?

Pet rats have certainly come a long way since they were first domesticated in a laboratory setting. Since they now live in even closer proximity to humans, they have made certain adaptions to our lifestyle and to the environments we keep them in.

Typically, wild rats are nocturnal – they awaken at dusk and spend the night searching for food, whereas they mainly sleep during the day.

Domesticated rats have a more flexible schedule and will spend their active hours whenever it makes most sense in their environment9. This means that your pet rats will often happily play with you in the afternoon, if this is the only time of day that works for you!

Pet rats have also adapted to the cages that we keep them in. Their wild counterparts dig burrows and build extensive underground tunnels to live in10.

Rats Cuddling in Cage
Photo by Annemarie Horne on Unsplash

Since it’s almost impossible to enable this behavior in captivity, pet rats have become used to living above ground. They still prefer to sleep inside a cave or in nests that they can build (from shredded paper, for example), though. And if you give them some soil to play with, they’ll likely rediscover their innate affinity for digging.

In favorable conditions, wild rats can form huge colonies (called a mischief) of up to several hundred individuals. In captivity, they are usually kept in smaller groups, and have since adapted their social behavior accordingly – they are less aggressive towards unknown rats, for example11.

A Mischief of Wild Rats
Wild Rats at the Karni Mata Temple (Rat Temple) India. Image by Simon from Pixabay

Pet rats should never be kept alone, though, as they are extremely social animals and suffer if they are isolated12,13.

All rats exhibit a behavior called “neophobia” – they naturally fear what they do not know. This trait has become a lot weaker in domesticated rats, though14. In fact, you may notice that your pet rats enjoy exploring new environments and objects. This is a great way to enrich their lives and keep them playful and engaged!

Another interesting difference between wild and pet rats is that wild rats have a broad range of swimming-related behaviors that are absent in laboratory and pet rats15. Your pet rats might enjoy playing with water (fishing for peas is a great activity!), but they are most likely reluctant to swim – so you should not take them in the water.

Can A Wild Rat Be a Pet?

Best rat food

You should not attempt to domesticate a wild rat, ever.

Wild animals belong in the wild. Pet rats have become adapted to life in captivity through many generations – a captured wild rat, on the other hand, is not fit for this lifestyle and will not thrive in a cage.

Conversely, pet rats are no longer used to fending for themselves and should not be abandoned in the wild.

Can Pet Rats Breed with Wild Rats?

Biologically speaking, pet rats and wild Norway rats can breed, as they are still members of the same species. However, a wild rat would probably show very aggressive behavior towards a pet rat. For this reasons, wild rats and pet rats should not be allowed to interact.

As you now know, pet rats have come a long way since their domestication. They are now perfectly adapted to being your beloved pet and interacting with you. If you want to find out whether your pet rats love you, this next article is for you!

Resources:

1. Schweinfurth MK. The social life of Norway rats (Rattus norvegicus). eLife 2020;9:e54020. https://pubmed.ncbi.nlm.nih.gov/32271713.

2. Kosoy M, Khlyap L, Cosson JF, et al. Aboriginal and invasive rats of genus Rattus as hosts of infectious agents. Vector Borne Zoonotic Dis 2015;15:3-12. https://pubmed.ncbi.nlm.nih.gov/25629775/.

3. Richter CP. Rats, man, and the welfare state. American Psychologist 1959;14:18. https://psycnet.apa.org/record/1960-02810-001.

4. Modlinska K, Pisula W. The Norway rat, from an obnoxious pest to a laboratory pet. eLife 2020;9:e50651. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6968928/.

5. Richter CP. Domestication of the Norway rat and its implication for the study of genetics in man. Am J Hum Genet 1952;4:273-285. https://pubmed.ncbi.nlm.nih.gov/13016540/.

6. Clark BR, Price EO. Sexual maturation and fecundity of wild and domestic Norway rats (Rattus norvegicus). J Reprod Fertil 1981;63:215-220. https://pubmed.ncbi.nlm.nih.gov/7277322/.

7. Davis DE. The characteristics of rat populations. Q Rev Biol 1953;28:373-401. https://pubmed.ncbi.nlm.nih.gov/13121239/.

8. Price EO. Domestication and early experience effects on escape conditioning in the Norway rat. Journal of Comparative and Physiological Psychology 1972;79:51. https://psycnet.apa.org/record/1972-26751-001.

9. Stryjek R, Modlińska K, Turlejski K, et al. Circadian rhythm of outside-nest activity in wild (WWCPS), albino and pigmented laboratory rats. PLoS One 2013;8:e66055. https://pubmed.ncbi.nlm.nih.gov/23762462/.

10. Barnett S, Whishaw I, Kolb B. The Behaviour of the Laboratory Rat. 1: Oxford: Oxford University Press, 2006. https://scholar.google.com/scholar?cites=6652998337171395037&as_sdt=2005&sciodt=0,5&hl=en.

11. Barnett S, Dickson RG, Hocking W. Genotype and environment in the social interactions of wild and domestic “Norway” rats. Aggressive Behavior 1979;5:105-119. https://onlinelibrary.wiley.com/doi/10.1002/1098-2337(1979)5:2%3C105::AID-AB2480050202%3E3.0.CO;2-U.

12. Hurst J, Barnard C, Nevison C, et al. Housing and welfare in laboratory rats: welfare implications of isolation and social contact among caged males. Animal Welfare 1997;6:329-347.

13. Calhoun JB. The ecology and sociology of the Norway rat: US Department of Health, Education, and Welfare, Public Health Service, 1963. https://archive.org/details/ecologysociology00calh/page/n7/mode/2up

14. Tanaś Ł, Pisula W. Response to novel object in Wistar and wild-type (WWCPS) rats. Behav Processes 2011;86:279-283. https://pubmed.ncbi.nlm.nih.gov/21215302/.

15. Stryjek R, Modlińska K, Pisula W. Species specific behavioural patterns (digging and swimming) and reaction to novel objects in wild type, Wistar, Sprague-Dawley and Brown Norway rats. PLoS One 2012;7:e40642. https://pubmed.ncbi.nlm.nih.gov/22815778/.

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