It won’t be an exaggeration if we say that rats have the most varied diet of all animals. It is believed that whenever rats are provided with two or more foods, they will not limit themselves to a single food item, but at least sample all of them. I have gathered some of the most essential information about what do rats eat in the wild. The dietary habit of rats undoubtedly makes them opportunistic feeders.
One of the primary reasons for this much variation might be due to the fact that rats are fearless of humans; as a result they often come across in the gardens or kitchen where they are fed with humans food; hence they have developed successfully their dietary requirements with the passage of time. For the same reason rats are often treated as pests or as laboratory animals unlike those houses where they are bred in captivity.
Rats need to eat constantly in order to utilize their energy. The amount of food increases with the age and it eats all throughout his life. This is not often observed in adults, as the growth becomes slow and the increase in the amount of food consumed per unit of body weight diminishes with increasing weight.
What Do Rats Eat in the Wild
Rats are actually rodents that are thought to evolve from insectivorous and omnivorous mammals inhabited at the time of dinosaurs. Nevertheless, seed-eating rats had emerged before 50 million years ago. Plants often provide food in a large quantity as compared to that of animals but the energy content in plants food is low; besides, it’s sometimes hard to access nitrogen from stems and leaves because of their tough fibrous cell walls.
Over the years rodents have developed a good many number of strategies for assimilating plants material such as gastrointestinal tract adaptations.
Rodents, including Australian rats and mice predominantly feed on insects and seeds. However, the large rat species are known to consume specialized diet such as broad-toothed rats are primarily herbivorous, tree rat are frugivorous (fruit-eating), whereas the water rats are exclusively carnivorous.
Unlike large rats, the small-bodied rats must eat more nutrition-rich food which vital to uphold their basal metabolic rate. There are quite a few Australian rats that are omnivorous and have a varied diet such as they consume fungi, insects, and fruits along with large number of seeds. While there are many rodents that feed on large number of food items, there are some species that change their diet according to the seasons and the availability of food.
(What Do Rats Eat)
Rodents living in the south-eastern Australia are known to change their diet from summer to winter. The New Holland mouse, for instance, primarily feeds on seeds in summer, while in winter it consumes a large number of stems and leaves.
Similarly, the smoky mouse and silky mouse primarily feeds on fruits and seeds in summer but in winter they rely on range of foods including insects, flowers, fungi, and spore cases (sporangia). On the contrary, the Hastings River mouse seems to have a much broader diet in summer, in which they consume seeds and leaves, while in winter they mostly consume leaves.
If we go to the arid zone, sandy inland mouse and spinifex hopping mouse appears to be primarily granivorous like many rodents inhabiting other continents including jerbils, kangaroo rats of south-west North America, and jerboas of North Africa.
Unlike these rodents, the Australian rats’ species seems to have much broader diet as they rely on stems, seeds, leaves, fungi, roots, and insects, depending entirely on availability. For the same reason they are classified as opportunistic omnivorous.
Rodents living in the arid zone have a specialized diet such as the desert mouse consumes stems of grasses and leaves and is thus classified as herbivore, whereas the central rock-rat has been reported to be specialist granivore.
The most specialized herbivore rodent is a broad-toothed rat inhabiting Southern Alps and is also found in button grass plains of Tasmania. This is an Australian rodent. These rats weigh around 120 grams and are generally known to feed on plants material all year round and their 52 – 87% diet is composed of grass.
They have specialized teeth that show strong tendency toward eating fibrous foods. Another herbivorous species is a greater stick-nest rat and it inhabits Franklin Island; these animals rely on stems and leaves, fruits of succulent plants and herbs, particularly of chenopods and the nitre bush.
(What Do Rats Eat)
There appears to be living many granivorous species in the Northern Australia. The Northern strip of Australian continent has a wide range of sizes in rats ranging from small rats to the large rabbit rats. The largest member of the Australian Old Endemic group is a black-footed tree rat and is frugivore as it generally feeds on fruits of pandanus which forms an essential component of its diet.
Giant White-tailed Rat
(What Do Rats Eat)
The giant white-tailed rat which is found in the rainforests of north-east Queensland eats fruits but it largely survives on omnivorous diet. It is known to eat insects, fruits, small vertebrates, nuts, eggs when available; whereas its close relative melomys species are generally herbivorous as they eat shoots, leaves, fruits, and roots.
Water Mouse and Water Rats
What Do Rats Eat
The water rat and the water mouse are the only species in the Australian native rodents that have the most unusual diet. Although they do not have specialized cheek (the carnassials) that are used for shearing flesh and are generally found in land carnivores like dogs and cats, but these species are carnivores.
Water rats primarily feed on crustaceans like shrimps and yabbies, dragonfly nymphs, insect, larvae, dytiscid diving beetles, and will consume almost anything including mosquito fish, goldfish, freshwater perch, certain small mammals, vertebrates, and occasionally birds. These Australian species are excellent swimmers and they mostly employ their thick tail while swimming in pursuit of prey.
Water rats generally eat their food on logs or boulders or sometimes on creeks and rivers. The remains of invertebrate exoskeletons are often found after they have devoured the flesh of animals. Although they do not have many teeth, mice and rats have developed incisors that are deep-rooted and which grows constantly all throughout its life.
Quick Facts about the Rats’ Diet
Broad-toothed Rat (Specialist Herbivore)
Primarily leaf, seeds, dicot, and grass
Greater stick-nest Rat (Herbivore)
Fruits of succulent plants particularly chenopods, nitre bush, and leaves
Black-footed Tree Rat (Mainly Frugivore)
Fruits especially pandanus, few termites, large seeds, and molluscs
Giant White-tailed Rat (Opportunistic Omnivore)
Birds eggs, fruits, seeds, fungi, arthropods, fruits especially coconuts
Water Rat (Opportunistic Carnivore)
Shrimps and yabbies, dytiscid diving beetles, goldfish, insect larvae, mussels, perch, odonata pulmonates
Bush Rat (Omnivore)
Monocots, dicots, stems, fungi, and insects
Swamp Rat (Herbivore)
Grass stems, leaves, roots, rushes