Captive Breeding of Harvest Mice

The Harvest mouse is sadly increasingly threatened in its natural habitat in the UK due to intensive farming, grazing and a reduction in hedgerows. Captive breeding programmes aims to commence a re-introduction programme by releasing mice into carefully selection and protected areas which have a variety of species of grass and reeds.

It should be noted that the only responsible way to release Harvest mice into the wild is through a captive breeding programme such as the Chester Zoo harvest mouse reintroduction programme or the New Forest Wildlife Park. You cannot simply release your own privately-bred harvest mice to the wild, not only does the Animal Welfare Act 2006 make this illegal but many of these lines are from mainland Europe whereas they need to be from a known wild origin.

It can also be advisable to breed at least 5 generations of harvest mice before releasing any individuals as part of a harvest mouse reintroduction, as this will highlight any genetic flaws and ensure you only release harvest mice that are healthy.

Releasing any animal without the adequate support and knowledge is very irresponsible and has a high chance of only condemning the animals to death.

Before becoming involved in a harvest mouse captive breeding programme it is advisable to keep a small group in a same-sex group as pets only. This will allow you to grow accustomed to their care.

Harvest Mice Behaviour

Harvest mice must be introduced at a young age to have the most chances of remaining stable and should be kept in pairs or small groups. Adult introductions are difficult and do not seem to have a high success rate. Same sex groups of either gender can be kept, with the mice often sleeping together in one nest.

Colony Aggression

Harvest mice pairs or colonies of Harvest mice can breakdown quite abruptly so must be monitored carefully with spare, secure tanks or vivariums available in case they need to be separated. The first warning sign of this can be some sniffing followed by one mouse leaping after the other and chasing it around the habitat, with the victim making abrupt, jerky movements or jumps away from the aggressor. This may then lead to a harvest mouse missing part of the end of their tail or having bites on their rear. If this persists, that it is important to separate as otherwise the victim may be killed.

Having more than one food bowl, and sprays of millet may help defuse the situation - it is vital to make sure that no mouse is bullied to the extent that they are no longer able to eat or drink in peace. Increasing the size of their enclosure may help, and personally I also recommend the use of the small silent spinner wheel. The mice can run side by side on this and it helps them use up their huge stocks of energy!

General Behaviour as pets

Harvest mice are virtually odourless and make a low maintenance pet if kept in male or female gender groups. They rarely bite providing they are handled well and some can be very friendly.

Breeding requires more vigilance since they do live in family groups or colonies as peacefully as other mouse species and can have outbreaks of violence.

If supplied with enough material a pet harvest mice will construct their own spherical nests to sleep in. Coconut fibre used for nesting birds such as finches can make a good material as well as plenty of hay and bedding.

Harvest mice jump and climb very well, using their prehensile tail as a fifth limb so it is important to furnish your Harvest Mice Environment with plenty of climbing material. The length of their jumps relative to their size is quite impressive, and if startled they may leap or ping a good 30cm.

Harvest mice can sense vibrations through the soles of their feet, allowing them to sense when a larger animal is nearby. They are cathemeral which means they are active at both night and day, with dusk being the most popular time. Harvest mouse behaviour has bursts of heavy almost manic activity followed by long naps. Harvest mice do not hibernate but would naturally spend most of winter underground so in winter you may observe less activity.

In captivity, it is important to let harvest mice exhibit as wild a range of behaviour as possible. Pet Harvest mice are unlikely to be bothered by household noise, but must not be kept in direct sunlight and are sensitive to aerosols, fly-sprays and air-fresheners. It is important to not smoke near your pet harvest mice.

Overview of Harvest Mice

The Harvest mouse is the smallest European rodent, native to Europe and Asia. In the wild it typically lives in fields of cereal crops like wheat and oats, and in reed beds long grass and hedgerows. Its fur is reddish-brown with a white belly, some individuals may weigh as little as 4g though an average adult may weigh around 7g, and a heavily pregnant female could weigh up to 15g.

Captive harvest mice live around 1.5 - 2 years. Like the African Pygmy Dormice they are arboreal so must have a habitat that allows for plenty of climbing opportunities and are generally a pet more to watch than to handle although some mice can be quite friendly.

Harvest mice can be kept with the company of their own kind providing they have been introduced at a young age. Pairs or colonies can breakdown without warning however, resulting in serious aggression and one or more mice being killed so they must be monitored carefully. See the Harvest Mice - Behaviour page for more information on colony aggression and introductions.

Harvest mice as pets cannot be kept in a conventional barred cage due to their small size and can easily chew out of anything plastic-based. A Harvest Mice Environment should provide natural enrichment such as branches, logs and nests. If provided with enough nesting material you may find your pet harvest mouse weaving the elaborate spherical nests they are best known for.

Pet harvest mice are active during day and night and take frequent random naps. A Harvest Mice's Diet consists mainly of seeds and insects but also nectar and fruit. They are very interesting, active pets to watch.

Harvest mice are sexually mature between 6-8 weeks of age and have a gestation period of 21 days. Like any animal, breeding should only be undertaken if you have thoroughly done your research and are prepared to give them the best quality of life as well as ensuring you have loving homes available for any offspring.