| The following editorial
comment summarises detailed information given within the LITERATURE REPORTS. Links to the
LITERATURE REPORTS are provided at the bottom of this box. BREEDING
SEASON: In the wild, pairs of bears, presumed mating pairs, have
been seen between March and October. In zoos, mating is generally seen
June to August but may occur as early as April or as late as September.
OESTRUS/OVULATION: Spectacled bears may be
monoestrous. However, at Lincoln Park Zoo it was usual for oestrus to be
seen in both June and August. Oestrus may be indicated by vulval swelling
and by increased occurrence and volume of vocalisations between the female
and male.
GESTATION/PREGNANCY: The gestation period is variable
with periods as short as 160 days and as long as 255 days reported. There is
probably a period of delayed implantation.
PARTURITION/BIRTH: In wild bears, most births
occur in December to February, during the heavy rains, such that cubs are
leaving the den when there are good fruit crops. In zoos in the Northern
Hemisphere, births have occurred most commonly in December to February. In
zoos in the Southern Hemisphere, birth months have been highly variable.
Video observation showed a female to give birth in a sitting position,
clean the cub and position it by a teat to feed; she ate the placenta.
NEONATAL/DEVELOPMENT:
Spectacled bear cubs are blind at birth with their eyes usually opening at
about 25 - 40 days. The ears were noted to be upright in one cub in the
ninth week. The first tooth may appear at 35-45 days. Cubs may be crawling
by six weeks of age, standing properly and walking by about nine weeks. One
set of parent-reared cubs was noted to be leaving the cubbing box at two
months, another set not until three months. Solid food may first be eaten at
about 80 to 90 days.
LITTER SIZE: Spectacled bears usually produce one
or two cubs. Litters of three are rare in zoos. Litters of up to four have
been recorded in the wild.
TIME BETWEEN LITTERS / LITTERS PER YEAR: No data is
available from wild bears. In zoos, there is usually a period of two years
between births, reducing to one year if the cub(s) do not survive.
LACTATION / MILK PRODUCTION: No data is available
from the wild, but cubs remain with their mother for up to a
year. In a zoo, cubs which were removed from their mother at nine
months of age and returned (for management reasons) two months later started
suckling again, but it is not known whether the female produced milk.
SEXUAL MATURITY: No data is available from the
wild. From captive bears it appears that females reach sexual maturity at
four to seven years and males usually at five years although males have been
observed to mate when as young as 3.5 years of age.
MALE SEASONAL VARIATION: --
LONGEVITY / MORTALITY: Spectacled bears may reach
nearly 40 years of age in captivity.
(References are available in detailed literature reports below) |
