Care Guide Reference

Cotton Eared Marmosets
Callithrix jacchus
South America

Introduction

Marmosets are a member of the Callitrichid family, they are small New World Monkeys from South America. Under current British Law, a license is not required to own one despite their less tolerant personality than that of the Sanguinus spp.

Adults weigh between 300-400 grams and can live up to 12 years. In the wild Marmoset groups vary in size between 3 or 4 individuals up to 20. Breeding is restricted to the dominant pair although other members of the group will take an active role in the care taking and upbringing of young. In captivity, the group should not extend to more than 10 individuals as in an enclosed space fighting may occur and illness will spread quickly.

Marmosets have a number of scent glands, which they will use to mark territory, items and even other Marmosets. They communicate by a number of high-pitched chirps, whistles and screeches, some Marmoset vocalisation occurs at a frequency above human hearing.

Housing Requirements

Marmosets should preferably have indoor housing with access to outdoors when it is warm, they need to be kept at a temperature of 25-29° C, if an outdoor enclosure is not possible [although this is the much preferred option], the diet will need to be supplemented with vitamin D3. Do NOT use a UV light. The minimum size cage would be 3ft x 3ft x 4ft which will allow them to jump and play, but the bigger the better. Branches, toys and swings should be added to provide environmental enrichment. Toys and branches can be moved around about every 6 months to give the animals a different routine.

Marmosets like to feel secure, so a nest box should be provided for them to sleep in, blankets or towels should also be provided, they will even snuggle up to cuddly toys.

For a family group of Marmosets, at least 2 feeding stations should be made available to avoid squabbling, and to ensure each member of the group eats. Water should be available at all times, they will become accustomed to using water bottles. To avoid floor foraging the feeding stations should be placed at least 1m above the ground.

Substrate should be absorbent and hygienic, wood shavings, bark, soil are all acceptable, a soft floor is recommended for breeding in case the infant falls.

To ensure the mental well being of these intelligent animals natural behavioural skills should be encouraged. Insect feeders can be used (above floor level) which release insects periodically encouraging the Marmosets to forage. Plenty of non-toxic, untreated branches should be provided for them to jump and play on but also they will gouge holes into them looking for insects and gum. Holes can be drilled into branches and insects or acacia gum inserted for the Marmoset to find. When it comes to environmental enrichment, use your imagination, forage food such as primate pellets can be hidden in and under things, make them work for their food, as well as providing nutrients it will also keep the Marmoset occupied to avoid the stereo typical behaviours of stressed animals developing.

Anything used to provide enrichment as well as sleeping quarters should be positioned 1m above the floor, in the wild Marmosets would rarely descend to the forest floor as they would be vulnerable to predators.

Breeding Marmosets

Marmosets reach sexual maturity between 12-17 months, in captivity they will breed all year round; in the wild they breed seasonally. They usually give birth to twins, occasionally a singleton and rarely triplets. The gestation period is on average 145 days, after the infant is born the parents will usually mate again, it is common for a nursing mother to also be pregnant. In a successful captive group, the average inter-birth interval is 154-178 days.

At birth infant’s weigh about 25-35g, the eyes are usually open but occasionally the eyes will remain closed for the first 3 days, and the infant will already have his milk teeth. The baby will stay with mum for the first 8-10 days to receive the necessary colostrum and they will nurse throughout the day. After this time the father or an older (usually male) sibling carries the baby on his shoulders. The mother will only nurse the infant at feeding time.

For the first two months the infant cannot thermoregulate and so relies on warmth from the caregiver, he has hairs on his fingers, which entwines with the caregivers fur to give the infant a better grip. A curly tail is a good sign of a healthy infant, a limp tail indicates the infant is in some distress.

An infant takes his first steps away from the caregivers between 4-5 weeks, at 6 weeks they start to eat solid food and will beg from family members, and at 14-16 weeks are weaned.

An infant will have his baby teeth at 27-28 days, the adult molars will begin to appear at 16 weeks and the permanent teeth appear at 48 weeks.

Parenting skills amongst Marmosets are not instinctive they are learned, these skills are picked up within family groups. An individual should remain within the family group for at least 2 litters in order to acquire these skills. Inexperienced parents without the necessary skills are more likely to reject, mutilate or kill their own offspring.

Within a family group, only one female reproduces; scent secretions and urine suppress the ovarian cycles of younger females even when sexually mature. Once the young female is removed and introduced to a new male normal cycles will be established, once this happens they cannot be re - suppressed by reintroducing the family group.

At the age of approximately 17 years, a female Marmoset will go through a ‘menopause’ called Reproductive Senescence, the males however remain fertile and are capable of siring offspring throughout their whole lifetime.

Nutrition and Diet

The diet needs to be kept interesting as well as nutritional. In the wild Marmosets will feed on gums and saps and small mammals. The Common Marmoset’s diet in the wild consists of 15% gums, unlike Tamarins, the Marmoset is a gummivore, and the Tamarin is classed as a seasonal gummivore. In captivity, they should be fed a high quality dry monkey pellet such as Mazuri Primate, or Exotic Nutrition’s New World Primate Diet; fruits, vegetables, insects and small vertebrates, they can also be offered the occasional treat. Acacia gum should be offered as a supplement in the captive diet as well as an environmental enrichment tool.

They should be fed twice a day, in the morning and in the evening. It is advisable to feed fruit and dried food at different times of the day, as fruit will usually be preferred over the more nutritious dry matter. Extra protein should be given to lactating females.

Cooked pasta, cooked oatmeal, cooked eggs (boiled or scrambled), dry cat or dog food, cheese and cooked chicken can all be included in the diet. Onion should be avoided at all costs as it can cause a type of anaemia in animals.

The diet should be supplemented with vitamin C, a Calcium and D3 supplement for which ZolcalD is recommended and a Multi vitamin powder. An obvious sign your marmoset is lacking in calcium is by their tails, if he is receiving sufficient amounts his tail will be full, if he is not receiving enough then his tail will be missing fur.

Treats can be given in small amounts. A small piece of cake or biscuit is often relished and can be useful before bedtime to ensure they have sugar in their system to sustain them overnight. Milk chocolate can even be given in very small amounts with no apparent ill effects. In fact some research facilities use Mars M&M’s as treats. It is also a good way to make friends and administer medication - liquid meds will be quickly absorbed into a piece of cake.

Insects and acacia gum should be fed as previously described to provide enrichment, extra protein and calcium.

A daily feed should include

AM: A mixture of 7 or 8 different fruits, for example (in terms of amount) 1/4 apple each, 1/4 pear each, 1/2 plum each, 1/4 nectarine, a chunk of melon etc, mammal vitamins, D3 powder, 1 drop pediatric vitamins.

During the day: Insect distribution via feeder, acacia gum spread on branches or from gum feeders.

PM: Cooked pasta, dried Primate diet which can be soaked in orange juice to make it more palatable, small piece of cooked chicken or 1/4 boiled egg per animal or a few dried cat/dog biscuits. Marmoset Jelly (Mazuri) should also be offered as it contains all the vitamins and minerals needed. Live yoghurt can also be offered, a favourite tends to be banana!

Before Bed: A marshmallow or small piece of biscuit.

As previously described, natural behaviour should be encouraged to ensure psychological soundness.

Illness

Unfortunately Marmosets are susceptible to many illness’ and viruses found in humans, including the common cold, the Herpes Simplex virus (virus that causes cold sores), Salmonella, E coli, Giardia, Tuberculosis (although rare), Measles; all of which can prove fatal; they can also be affected by internal parasites. Be aware of any change in physical condition, or stool consistency. Ideally an annual health check should be carried out and stool samples taken and studied for bacteria that can affect both primate and human health. The list of illnesses is far too extensive to go into here, so one should be very cautious when dealing with these animals if you are ill!