[EN] The reproduction of Octodon degus

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The reproduction of the Octodon degus is like this rodent: out of the ordinary. It is indeed one of the rodents with the longest gestation period of the order of rodents, with 3 months before giving birth. In the wild, the reproduction cycle is annual, rarely biennial. In captivity, it is shorter and the litters are often larger. Many octodon owners end up with unwanted babies, either after a mistake on the sex of the octodons, or after the acquisition of a pregnant female. Unfortunately, this leads to abandoning or to the emergence of genetic pathologies, or even to their consolidation, as for the diabetes. For breeders, amateur or professional, the use of a standard is an ideal tool to avoid this kind of problems and contribute to the good health of the litters.

The Octodons.fr website strongly encourages all its readers to prefer adoption rather than buying from pet shops or breeders. However, the setting up of breeding standards allows to help regulate health problems and to avoid physical malformations in octodons.

Octodon degus en gestation

The reproduction in the Octodon degus


Age at weaning : 72 to 75 days 1.
Sexual maturity : between 3 and 9 months.
Duration of the estrous cycle : 18 to 21 days.
Gestation period : between 87 and 95 days.
Average number of pups per litter : 5,5.
Minimum and maximum litters : 1 to 122
Number of udders: 8.
Nursing duration: 21 to 40 days.


Anatomie

Male and female octodons are often confused, which leads to unwanted litters. When acquiring a new degu, the sex of the animal should be checked. Males have a greater distance between the urinary cone and the anus than females. We can also distinguish in females a vertical “bar”, which turns out to be the vaginal lips. 

Distinction de sexe entre un octodon mâle et un octodon femelle

Sex distinction between a male and a female octodon

The female octodon can give birth to a maximum of 12 babies per litter. However, they have only 8 teats to feed them, which can induce the death of some babies. The placenta of octodons is very similar to that of guinea pigs3, and develops at the beginning of gestation, before degenerating a little before giving birth. Octodons are considered homologous to other Hystricognaths, as this is one of the particularities of this infra-order4.

Baby O. degus – Koko Kitto Katsu

The genitalia of the male octodon is characterized by a perianal circle with the penis pointing backwards. The testes are inside the abdomen, as in most caviomorphs5. The octodon presents a low testicular thermal sensitivity, with a very small difference with its internal temperature. It can be noticed that the penis of the octodon has small spikes6, to favor reproduction. 

⚠️Penis of an Octodon degus⚠️

Male octodons show (A,B) a non-erect penis, and (C,D) an erect penis with extended spikes7.

Penis of an adult and juvenile Octodon degus. (Photos de T. J. Jechura.)

Representation of a spermatozoon of the Octodon degus.

Octodon degus spermatozoa are similar to those of its family, with a flattened, rounded head, 7.7pm long by 5.9pm wide with dome-shaped protrusions. The tail is longer, with 41pm. What distinguishes the spermatozoa from the octodon is the area of the acrosome surrounding the nucleus, which has an inverted U shape8.

 

The reproduction of the octodon in the wild

In the wild, the octodon breeds only once or twice a year, during the rainy season9. They give birth to an average of 5 pups per litter after 90 days of gestation. The females raise their young in “nurseries”10, with other females before they can leave the burrows, after a few weeks. Young octodons are fertile from 3 months of age, but on average, sexual maturity develops at the age of 9 months, at the beginning of the breeding season.

The reproduction of the octodon in captivity

In captivity, we can observe many pregnancies in the octodon, due to the housing conditions as a greater exposure to light and heat. Females can have up to 4 litters per year9, which can be harmful to their health.

Mating

During mating, the male octodon makes calls, the function of which has not yet been well determined11, thus announcing a probable birth in a few months. To mate, the male octodon climbs on the female, then fertilizes her, thus allowing the gestation process to begin. Mating is usually quick and can be confused with dominance behaviors on another octodon, where one climbs on the other.

Young octodons with adults during a resting phase – Brianna Laude

The estrous cycle of the octodon lasts between 18 and 21 days, and the female can have several litters, as the octodon has a 50% chance of starting a new post-partum cycle in captivity6. It is therefore important to remove the male at the end of gestation, to avoid the female to succeed the litters. He can be reintroduced one week after the birth of the pups (the duration of fertilization is only 4 days). During the breeding season, the vulva of the females opens visibly, and remains open until the end of the season, for several weeks. This phenomenon is related to the perforation of the vaginal membrane and not by the penetration of the male12.

With age, octodons become less fertile and can produce up to 40% less sperm (at the age of 5 years), which will limit their reproduction13. Males have a higher testosterone level in the wild than in captivity14, especially during breeding seasons15. This increases the chances of fertilization, and thus, perpetuate the species. 

After mating, we can notice a “plug” that closes the vagina of the female. This is a formation of mucus and sperm, which is found in other rodents, such as mice and rats. This clump would serve as “protection” against bacteria, and would also allow not to “damage” the seed of the evil. Sometimes the plugs break off, either after mating or during gestation12.

Octodon degus enceinte

Gestation

The gestation period of the octodon is exceptionally long for a rodent. Gestation lasts about 3 months, more precisely between 87 and 95 days. The length of gestation is due to slow fetal growth and late development of the babies, which are born with fur and can open their eyes very quickly. The octodon can carry between 1 and 12 babies2, but the average litter size is 5 to 6 babies. Younger and older octodons generally have smaller litters.9.

Embryo development starts with blastocysts, 4-5 days after mating. It is only after one week that the embryo implants to the maternal tissues (interstitial attachment of the ectoplasmic trophoblast). After 12-13 days, the amniotic cavity is formed, followed by the allantoic membrane at about 30 days. Finally, the chorio-allantoic placenta is formed 30-35 days after mating.

The weight of the pregnant female should be closely monitored, as well as throughout the lactation period. The female will continue to lose weight for a few weeks after parturition, before regaining her initial weight.

Monthly weights of breeding Octodon degus females over an 8-month period during the breeding season, divided into pre-breeding, gestation, and postpartum periods. The 230g line indicates the average non-pregnant (adult) weight for the females in the sample.

Birthing

The birth is a trying moment for the females and can take several hours according to the number of expected babies. It is advisable to leave the octodon quietly in its cage, in a calm place, until the end of the birth. The babies are born fully furred, active and with their eyes open, but remain in the nest for two weeks before venturing out into the outside world. In captivity, they may come out earlier in the cage. They can also walk after a few hours, stand on their hind legs and even give their first calls. During the first 2-3 days, the pups sleep in a parallel formation, oriented in “head to tail”. From day 3 on, they begin to settle in a more crowded, “pile” formation on top of each other, like adults2.These parallel formations can be found up to day 8. They have also been observed in other hystrocomorph rodents, and could be used to better detect predators. However, as octodons are semi-feeding animals sleeping in burrows, this ability is not essential for their survival.

The birth ratio of octodons is 1.1:1, or about 100 females to 110 males12.

Growth of O. degus

An important part of reproduction in the octodon is the growth of the young. This must be monitored in order to verify its stability and that the little rodent is in good health. At birth, the baby octodon is about 13g, but this can vary from 8g to 17g2 depending on the size of the litters. From the first days, the pups are able to move independently, but also to start grooming, and already begin to nibble food. The young tend to stay in compact groups and do not move away from their parents. From the 8th day, the young storks have the ability to behave like adults, to wash themselves properly, and to freeze if they hear an alarm call.

Baby Octodon degus agouti

The evolution of the weight can depend on the sex of the octodon, the males having a tendency to put on weight more quickly, but also on their origins (some colonies put on weight more quickly). In the wild, the young octodons tend to gain less weight than in captivity, this can be explained in particular by the food and the living conditions. If the octodon gains weight in a regular way, we can note variations of +/- 5g compared to the average weight.

Age (days) Weight (gram)
1 13g
2 14g
3 14,5g
4 15g
5 18g
6 19g
7 20g
8 22g
9 23g
10 25g
11 25g
12 26g
13 27g
14 28g

As with the early days, weight differences can be noted throughout growth, increasing with age.

Age (weeks) Weight (gram)
0 13g
1 20g
2 32g
3 41g
4 58g
5 72g
6 88g
 

Weight (in grams) of young octodons from the day of birth to the 14th day.

Parenthood in degus

Breeding in “nurseries”

The Octodon degus organizes in the burrows nurseries in a common nest. These common nests are still a question for scientists, indeed, they do not seem to bring “advantages” in the short term for the species16. Male and female degus from the same clan and unrelated to the pups show little or no aggression towards the babies. The young are thus raised by several females and do not seem to differentiate between their mothers and the nurse octodons17. Females with offspring also do not differentiate between litters. Octodons rely more on sounds and acoustic signals to call nursing females into the burrows, or to group baby octodons. When the adults are present, the babies settle underneath to sleep in warmth. If the adults are not present, the young octodons will try to hide to sleep in safety.

Baby octodon degus at the age of 5 days – Denise Aretino

Careful attention should be paid to the health of the mother and access to a social group, babies should not be raised in isolation, handled with their parents (no separation, even for a few minutes). Also, they must be weaned at the right age, otherwise they may develop behavioral and socialization problems6. It is possible to touch them after birth, but contact should be kept to a minimum until their first natural outings.

The male has as important a role as the female in the rearing of the babies, if he is castrated, he can be left with the female without any problem. Also it is advised to leave the other females of the group, if there are some, which will also help to take care of the litters. Leaving other adult octodons can relieve the female of some of the breeding. The pups can snuggle with other adults and the mother can better feed and rest.

The Octodon degus is a very social animal, it needs many interactions with its peers. These interactions are essential for their physical and psychological development. They learn to respond in a specific way to their parents. When this socialization is disrupted with their parents, octodons show a “hospitalization syndrome”, which is a mental regression, resulting in deficits in vocal behavior, personality development, intellectual and social abilities and mental disorders.
Parental interactions are numerous, including nose touching, grooming together and carrying one of the babies. Interestingly, the father generally spends less time with the pups and his interactions are more centered around mimicry games. As the pups begin to emerge and become less dependent on their mother, their contact with the mother decreases, but the amount of contact with the father increases during this period. During the first few weeks, both parents actively care for the newborns. They huddle and cover them to maintain their body temperature and protect them. The octodon parents spend 80% of their day watching the young, either by staying in their surroundings or by putting themselves on them.

Breastfeeding

Shortly after the birth, the young octodons taste their first suckling from the 8 teats of their mother. They will start by sucking, lying on their back, before changing position with their growth. It is via the mother’s milk that the octodon’s antibodies are transmitted, in order to protect its descendants. As they grow, octodons force their mother or nurse to lie on their side to nurse. Females usually nurse their young for a month, after which they are able to feed themselves. Baby octodons, however, begin to eat solid food very quickly, usually after one or two weeks18. As early as 3 days, they can gnaw on feces, which allows them to acquire microflora and bacteria essential to their digestive system. Feeding time is on average 25 minutes, with rest periods of 3 to 5 minutes for the babies. Octodons tend to change their teats regularly, they cling to the female with their front legs while pushing with their back legs.

Young Octodon degus 12 days old during a feeding – Marie Christine Ratton

Young Octodon degus 12 days old during a feeding – Marie Christine Ratton

The female octodon uses a lot of energy during lactation. Indeed, she transforms very quickly the ingested food into milk. It is important that females have access to enough food during lactation, in order to be able to feed properly. While the solids, fat, protein and ash content of the female’s milk is stable, the carbohydrate content decreases sharply as lactation progresses19. This is related to the high energy needs of octodons at birth, which tends to decrease with the ingestion of the first solid foods. At the end of lactation, the level of cortisol (stress hormone) strongly decreases in lactating females.

Rate in % of milk composition in the breastfeeding environment19. Protein Carbohydrates Fats Solids
4,4 2,7 20,1 30,5

Independence and weaning

Young O. degus a few weeks old.

During its growth, the young octodon will learn to interact with its fellow creatures. This starts with their brothers and sisters, whose interactions increase with time. Moreover, they will also meet the other rodents of the clan. After a few days, the young begin to explore their territory, and thus to go further and further away from the birthplace. Their physical and mental development is greatly affected by the separation from their siblings and/or parents. The young must stay with their social group as long as possible, without changing their environment, otherwise they will be stressed.

Weaning is a key moment in the life of animals. It is the moment when the animal is able to live by itself, without depending on its parents for food or protection. In the octodon, weaning corresponds to the end of the teeth growth, that is to say around 72 to 75 days old. Weaning an octodon before this time may disturb the good physical and mental development of the rodent, and induce future behavior problems. In the wild, octodons naturally disperse when the burrow is overcrowded, but some stay longer with their parents.

During weaning, the enzymes that digest milk (lactase) are replaced by enzymes to digest solid food (sucrases). This process of enzyme change within the digestive system is very slow, hence the need for young octodons to be breastfed for at least 3 weeks. It is during the weaning that they also acquire their intestinal flora, essential to their good health. It is possible to start the intake of fresh plants during weaning, because it is at this time that they start to consume them in the wild.

Development and adolescence

Young octodons with adults during a resting phase – Brianna Laude

Octodons take up to a year to complete their physiological development, it takes them between 53 and 55 weeks to become adults20.

Octodons have a rather long puberty21, which remains rare in rodents. In general, females reach their sexual maturity around 7 weeks, against 12 for males. However, if it is advised to remove the males around 4 to 6 weeks for safety reasons, weaning is reached around the 11th week. This is due to the fact that in captivity, it happens that the young reach puberty earlier.

Social dispersal

Social dispersal is when an animal leaves its social group in search of a new territory. There are three major stages to this social dispersal: leaving the birth burrow (departure), crossing unfamiliar environments (transfer), and finally integrating into a new group/territory (settlement). This behavior can be observed in some species, such as birds. 

In octodon, natal dispersal occurs in the vicinity of birth burrows22, equally between females and males although degus often change social groups during their lifetime23. Dispersal also appears to correlate with overcrowding in burrows, especially when females give birth to large litters22.

Please note that this article was translated with the help of DeepL. If you notice any mistakes, please send us an email at octodons.lesite@gmail.com! Thank you for your help!

Sources

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  3. The Ultrastructure of the Trophoblastic Layer of the Degu (Octodon degus) Placenta: a Re-evaluation of the ‘Channel Problem’[]
  4. The subplacenta in Octodon degus and Petromus typicus–two hystricognath rodents without significant placental lobulation[]
  5. Anatomy of Reproductive Tract in Octodon degus Molina: À Nonscrotal Rodent[]
  6. Husbandry and Breeding in the Octodon degu (Molina 1782)[][][]
  7. Husbandry and Breeding in the Octodon degu (Molina 1782)[]
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  9. Handbook of Exotic Pet Medicine[][][]
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  11. Vocalisations of the Degu Octodon degus, a social caviomorph rodent)[]
  12. Reproductive characteristics of hystricomorph rodents[][][]
  13. Ageing and testicular function in Octodon degus[]
  14. Social cues and hormone levels in male Octodon degus (Rodentia): a field test of the Challenge Hypothesis[]
  15. Free and total testosterone levels in field males of Octodon degus (Rodentia, Octodontidae): accuracy of the hormonal regulation of behavior[]
  16. An experimental examination of the consequences of communal versus solitary breeding on maternal condition and the early postnatal growth and survival of degu, Octodon degus, pups[]
  17. The Lack of Recognition of Lactating Females by Infant Octodon degus[]
  18. Dental Eruption Chronology in Degus (Octodon Degus)[]
  19. Temporal dynamics of milk composition of the precocial caviomorph Octodon degus[][]
  20. Male degus, Octodon degus, modify their dustbathing behavior in response to social familiarity of previous dustbathing marks[]
  21. Chronotype changes during puberty depend on gonadal hormones in the slow-developing rodent, Octodon degus[]
  22. The influence of group size on natal dispersal in the communally rearing and semifossorial rodent, Octodon degus[][]
  23. Instability Rules Social Groups in the Communal Breeder Rodent Octodon degus[]

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