Rat

The domestic rat is derived from the wild brown rat (Rattus norvegicus), which is native to northern China and Siberia but has spread globally through human activity. Selective breeding of rats for laboratory research began in the 19th century, and the same docile, manageable bloodlines were subsequently developed as companion animals — today's 'fancy rat' is the direct descendant of those early laboratory strains.

Rats are among the most cognitively capable of all small pets. They have been demonstrated to solve multi-step problems, navigate complex mazes, learn their own names, respond to verbal commands, and even show empathy — in research studies, rats have been documented choosing to free trapped companions rather than claim available food for themselves. Their intelligence makes them highly trainable and deeply engaging as pets.

Rats are social animals and must never be kept alone. A single rat deprived of companionship and adequate daily human interaction will develop signs of depression, including reduced activity, loss of appetite and susceptibility to illness. Same-sex pairs or groups are the gold standard for rat keeping.

Rats need a spacious, vertically oriented cage that allows climbing, exploration and multiple levels of activity. A minimum cage size for a pair of rats is 60cm W x 40cm D x 80cm H; the more space provided, the better. Multi-level cages with ramps, platforms and shelves make full use of vertical space and provide physical exercise within the enclosure. Bar spacing should be no larger than 1.5cm to prevent escape of small individuals. All cage doors and access points must have secure, rat-proof latches.

Essential cage fittings include rat hammocks or hanging pouches for sleeping and resting (rats love to sleep suspended), a solid-based litter tray in the preferred toileting corner filled with dust-free paper litter, a ceramic food bowl, a sipper water bottle, wooden or cardboard hides for privacy, and a variety of toys including ropes, ladders, tunnels and chew items.

Substrate on cage levels can be paper-based bedding, fleece liners (washable) or kiln-dried aspen shavings. Pine and cedar shavings must be avoided due to aromatic oil content which can cause respiratory problems. Rats are social, curious animals and the cage should be positioned in a main living area where the family spends time, allowing the rats to hear and see their human family throughout the day.

Rats are omnivores and thrive on a varied diet that mirrors the diversity of their natural feeding range. The dietary foundation should be a quality rat-specific pellet or block — a quality rat/mouse-specific pellet formulation is designed to meet the complete nutritional requirements of pet rats and minimises selective feeding. Approximately 50–60% of the diet should come from pellets.

The remainder should come from a varied rotation of fresh vegetables and small amounts of fruit — suitable vegetables include broccoli, capsicum, corn, peas, carrot, leafy greens, cucumber and sweet potato. Fruits such as apple (no seeds), blueberries and banana can be offered sparingly as treats due to their sugar content. Small amounts of protein can be offered 2–3 times per week — cooked chicken, a small piece of boiled egg, low-fat yogurt, or a small dog biscuit all work well.

Mixed seed and grain diets can be offered as a treat or foraging activity, but should not replace the pellet base — rats often selectively eat preferred components and leave behind nutritionally important items. Never feed chocolate, caffeine, raw dried beans, raw sweet potato, sticky foods, carbonated drinks, or very high-fat, high-salt human foods. Fresh water must be available at all times, offered in a sipper bottle (more hygienic) or a heavy bowl that cannot be tipped.

Domestic rats are often described as the dogs of the small pet world — they learn their names, respond to training, seek out and enjoy human company, and can form strong individual bonds with their owners. They are active, playful and rarely sit still during waking hours. Most rats accept handling readily and will climb onto their owner's shoulders, explore pockets and nest in hair given the opportunity. Their short lifespan means the bond formed is intense and, for many owners, deeply felt.

Rats should be handled daily from a young age to maintain tameness and social bonding. The best approach for a new or nervous rat is to allow it to come to you — offer your hand flat in the cage and allow the rat to investigate and climb on at its own pace. Once a rat steps up reliably, begin picking up gently by cupping both hands under the body and lifting smoothly. Rats should never be grabbed suddenly, held by the tail, or restrained tightly.

Out-of-cage time of at least one hour per day in a safe, rat-proofed area is important for physical health and mental enrichment. Rats are escape artists and will investigate every gap, cable and accessible surface — prepare the free-roaming area carefully. Multiple rats should all be handled regularly to maintain individual bonds with their human carers.

Rats are highly intelligent and require active daily enrichment. Rotate a selection of toys within the cage every few days — ropes, tunnels, cardboard rolls, willow balls, hanging treats and climbing structures. Puzzle feeders — hiding food in paper bags, folding it into cardboard tubes, or placing it in a foraging ball — engage the rat's natural problem-solving and searching instincts and are one of the most effective forms of enrichment.

Teach tricks using positive reinforcement with small food rewards — rats can learn to spin, wave, navigate an agility course, retrieve objects and much more. The training process itself is as enriching as the trick outcome, as it provides mental engagement and strengthens the human-rat bond. During out-of-cage time, introduce novel safe objects for investigation — an empty box, a paper bag, a shallow tray of shredded paper — to provide sensory novelty.

Respiratory infections (mycoplasmosis): The most common serious health issue in pet rats. Caused primarily by Mycoplasma pulmonis, which is present in almost all rat populations. Signs include sneezing, clicking or rattling breathing sounds, and laboured breathing. While it cannot be cured, it can be managed with veterinary treatment (antibiotics, anti-inflammatory medication). Ensure good cage ventilation, avoid pine and cedar shavings, and seek early veterinary attention at the first signs of respiratory change.

Tumours: Rats are prone to developing benign and malignant tumours, particularly mammary tumours in females, which are often fast-growing. Desexing females significantly reduces mammary tumour risk. Regular handling allows early detection of any lumps.

Hind leg degeneration (HLD): A progressive neurological condition common in older rats, causing weakness and loss of function in the hind limbs. Currently no cure; quality of life management includes ramps and adjusted cage layout.

Lice and mites: Can cause itching and hair loss; treat with veterinary-recommended small animal parasite treatment and cage disinfection.