Do gerbils need a friend? Pairs, clans and split cages

Do gerbils need a friend?

Yes. The RSPCA says gerbils should never be kept on their own, and Gerbil Care UK says the only exceptions are serious illness, declanning or waiting for a new partner. In the wild, the RSPCA says, gerbils live in family groups of two to 15. PetMD warns that gerbils kept alone can become depressed, and the MSD Veterinary Manual says living alone may be stressful.

Company isn't a nice extra for gerbils. Gerbil Care UK lists what they do together: groom each other, build burrows as a team, sleep curled up for warmth, drum their back feet to warn each other of danger, and play. Watching a pair work on a tunnel together is half the fun of keeping them.

How many gerbils should be kept together?

Two. Gerbil Care UK says a pair is the most stable group, because the fewer gerbils there are, the fewer challenges there are to the top gerbil. Wood Green says gerbils are happiest in small same-sex family groups.

Gerbil Care UK says males should never be kept in groups of more than four, and suggests a group of five is better as a pair and a trio. Tank sizes are Wood Green's minimums; see our gerbil cage size guide for more.

Are gerbils friendlier than hamsters?

With their own kind, yes, by a long way. The RSPCA says Syrian and Chinese hamsters should always live alone, and even dwarf hamsters don't need company to be happy. Gerbils are the opposite: they need it. With people, Oregon Humane Society says gerbils are friendly by nature and rarely bite once used to you. They are also busy in daylight in short bursts, so you see more of them than of a hamster, which the RSPCA describes as active at night.

That said, Wood Green and Gerbil Care UK both describe gerbils as a pet to watch rather than cuddle. Most tolerate a short handling session rather than ask for one. If you want a pet that sits on your lap, they may disappoint; if you want to watch a little team at work, they won't. Compare the two in our guides to gerbils as pets and hamster care.

Do gerbils get attached to their owners?

They learn to trust you, and some come to you happily, but their real bond is with each other. Gerbil Care UK says a patient owner can earn a gerbil's trust until it walks into a hand or tube on its own, and gentle grooming nibbles on your fingers mean it is accepting you. That trust grows fastest when a gerbil feels safe, which it does with a partner beside it. Our guide on how to tame a gerbil shows the steps.

Can gerbils live alone after one dies?

For a short time while you find a new friend, but not for good. The RSPCA's rule that gerbils should never live alone applies to older gerbils too. Losing a partner is hard on the one left behind: it has no one to sleep with or groom with. Gerbil Care UK says no gerbil is too old for a new partner, and it has paired elderly gerbils successfully.

• Keep the survivor's routine and tank the same for now
• Give it extra nesting paper, since it has lost a warm sleeping partner
• Contact a gerbil rescue for a same-sex single needing a home
• Pick a partner within about six months of age if you can, as Gerbil Care UK suggests
• Or choose a pup under eight weeks, which Gerbil Care UK says bonds most easily with an adult
• Set up a split cage before the new gerbil arrives

If you are not ready for a new gerbil, ask a rescue whether they have a lone gerbil who also needs a partner, or whether they can rehome yours into a pair. Our guide to where to get a gerbil lists rehoming options.

How to introduce gerbils with a split cage

A split cage keeps two gerbils side by side with a mesh wall between them, so they learn each other's scent before they can touch. Gerbil Care UK warns against putting strange gerbils together on neutral ground or straight into an established group, which it says risks serious injury or death. It adds that tanks side by side don't help, because gerbils know each other by scent, not sight. This is Gerbil Care UK's method.

1. Make a small split space. Divide part of a tank with a fine mesh divider framed in untreated wood, standing on the tank floor so no one can push under it. Each side should be about 40 × 40 cm (16 × 16 in), and no more than about 75 × 45 cm (30 × 18 in).
2. Close the top. Fit a temporary mesh lid weighted down so no one can climb over the divider.
3. Keep it plain. Use only 2.5 to 5 cm (1 to 2 in) of bedding, a water bottle on each side, plain nesting paper and scattered food. No wheel, sand bath, bowls or toys; willow sticks and cardboard tubes are fine.
4. Swap sides every day. Move each gerbil to the other side once a day so they sleep in each other's scent. Don't clean or change anything else, and keep handling to a minimum.
5. Watch for good signs. Sleeping against the divider, eating side by side, nose bumping and copying each other's activity all mean it is working. Expect this to take at least two weeks, and up to a couple of months.
6. Swap, then lift. Do a final side swap about two hours before lifting the divider, wearing thick gardening gloves in case you need to separate them.
7. Watch closely. Stay for the first three hours and keep checking for the rest of the day. Boxing, sniffing, light chasing and small squabbles are normal. Sleeping together means it has worked.
8. Build the tank back up slowly. Leave the bare setup for two days, then add one thing at a time, such as the nest box, then the sand bath, then the wheel, and more space and bedding in stages over about two weeks.

Gerbil Care UK says that after two or three failed attempts, a pair may never bond, and each gerbil needs a different partner.

Why gerbils fall out: declanning

Declanning is when a gerbil group breaks down and one gerbil turns on another. In the wild, Gerbil Care UK explains, the loser of a dominance fight leaves to start its own group. In a tank it can't leave, so the fighting goes on. Gerbil Care UK says it happens most often in adolescence, around 6 to 8 months old, and in bigger groups. Wood Green notes fight wounds often appear on the legs and face, and Gerbil Care UK says the losing gerbil's wounds are usually around its rear.

Signs of declanning

• They stop sleeping together
• Constant, forceful chasing, hard enough to bang into the glass
• One gerbil pinning another down, or shoulder barging
• Side arching, where a gerbil makes itself look bigger
• One gerbil cowering away from the rest
• Blood on a gerbil or in the tank
• One gerbil stopping another from eating or drinking

Light chasing, boxing and play fighting are normal ways gerbils settle who is in charge. What matters is whether it keeps going and gets worse.

What to do

If there is no blood, Gerbil Care UK says not to separate them straight away, because once apart they may need a long re-bond with no guarantee. Instead, strip the tank back to a bonding-style setup: about 2.5 cm (1 in) of bedding, one nest box, two water bottles and scattered food. Keep it like that for at least a week, then add items back about a week apart. If blood is drawn or a fight won't stop, separate them and see a vet for any wounds.

Act quickly once you separate: Gerbil Care UK says gerbils can forget each other's scent within 48 hours, sometimes within hours. A split pair then needs new partners. In a trio, Gerbil Care UK says to remove the gerbil being bullied rather than the top gerbil.

Common causes of fallouts

Gerbil Care UK lists many triggers. The ones you control are: groups that are too big, a single bowl or bottle one gerbil can guard, too many separate nest spots, multi-level tanks with areas to claim, a big sudden jump in tank size, a full clean without keeping about a fifth of the old bedding, and separating one gerbil for a vet visit. Take both gerbils to the vet together. Our gerbil behaviour guide explains thumping, boxing and other body language.

Can I leave my gerbil alone for a week?

No. Gerbils need fresh water, food and a quick health check every day, and a blocked bottle leaves them with no water until someone notices. The RSPCA advises asking a responsible friend or family member to look after them, introducing that person before you go and showing them the routine. Keep the gerbils in their usual tank with their usual food, and only move them if you must, to keep stress down. The RSPCA also says small pets not used to travel shouldn't come on holiday with you.

• Write down the daily routine: water, food amount, quick look at every gerbil
• Fit two water sources, such as two bottles, and show how to check they flow
• Leave enough food, pre-portioned per day
• Leave your vet's number and an emergency vet's number
• Ask the sitter not to do a full clean while you are away

For everything else a pair needs, see the complete gerbil care guide.