ECOLOGY AND BEHAVIOR OF 3 WILD ORPHANED BROWN BEAR CUBS IN SPAIN
The brown bear is a typical K-selected species, with a
long life and low birth rate. Maternal care includes nutri-
tion and protection and almost certainly conditions later
adaptive behavior. In European populations maternal care
extends for about 18 months and weaning occurs at 1
year (Camarra 1989).
The study of wild, motherless bear cubs provides in-
sight into instinctive versus learned behavioral patterns.
For the small, fragmented South European brown bear
populations that presumably are near or under minimum
viable population numbers (see Berducou 1990 for a re-
view), this information can help managers decide whether
to leave alone or capture orphaned cubs, which could be
used for reinforcement programs.
The survival of orphaned black (U. americanus) and
brown bear cubs older than 5 months has been reported
by Erickson (1959), Johnson and Leroux (1973), Payne
(1975), and Jonkel et al. (1980). As far as we know,
however, detailed information on monitored wild orphan
cubs has never been published. This study provides gen-
eral information on the ecology and behavior of 3 wild
orphaned brown bear cubs over autumn, denning, and den
emergence periods, including details on diet, habitat use,
and interspecific relationships.
The 3 cubs were sighted with their mother on 23 and
26 May 1991. The female, easily identified by her miss-
ing hind leg, had been regularly observed in the area since
1984, with litters in 1984 and 1989. From late July 1991
the cubs were always observed unaccompanied and the
female was no longer located. Given her previous
observability, her disappearance strongly suggested that
she had died. From 3 October 1991 to 6 May 1992, the
orphans were sighted on 47 days (109 hours and 52 min-
utes of observation time), and their recent tracks were
located 6 other days. From 9 May to 1 November bears
were observed on 7 days and their tracks detected on 4
other days (Table 1).
Autumn
From 3 October 1991, when regular monitoring began,
to 3 December 1991, when denning started, the cubs were
observed for 27 hours and 45 minutes. They spent 97.5%
of observation time foraging, 1.5% walking, and 1.5%
playing. In October we observed them feeding only on
hazelnuts (Corylus avellana) (n = 6 days); in November,
on rowan (Sorbus aucuparia) berries (37.5% of the ob-
servation days), grass (37.5%), and hazelnuts (25.0%;
n = 16 days); and in December, on grasses (75.0%) and
rowan berries (25.0%; n = 4 days). To feed on hazelnuts
and rowan berries they often climbed trees, showing great
skill in handling branches despite their lack of knowl-
edge of never having eaten such fruits. They were active
during all daylight hours, but mainly in the early hours of
the morning and late in the afternoon; if these observa-
tions roughly reflected their daylight activity pattern, it
was similar to that of the radiotagged Cantabrian adult
male studied by Clevenger (1991). Cubs were always
sighted walking and foraging a short distance apart and
were never located at the den. Their general appearance
was excellent, and they obviously gained weigh
Intra- and Interspecific Interactions
Several times we recorded interactions between the
orphans and other potentially dangerous species. On 13
April 1992, when the yearlings were about 15 months
old, they encountered an adult bear. The adult and the
yearlings watched each other from 100 m apart for 2 min-
utes. Following a small landslide nearby, they ran off in
opposite directions. On several occasions we noticed the
presence of wolves in the same area as the orphans, but
we did not observe an interaction. The orphans shared
the range with wolves for months without injury. Free-
ranging dogs also were present. On 12 May 1992, an
orphan stopped grazing and ran away from sheep dogs.
We recorded 2 types of interactions with humans. Most
of the time the orphans could hear the usual noises from
the village and the road <1 kilometer away. Even when
noises were especially
loud (shouting, car horns), the bears
appeared attentive only for a few seconds. However, on
6 occasions they noticed the unusual presence of people
(wardens, hikers, researchers) 100-500 m away. On these
occasions they were alert, looking around and sniffing.
In addition, once they moved away, once hid in bushes,
and once ran away; but they always reassumed their ac-
tivity in the same area when danger disappeared. Thus,
they seemed able to distinguish non-dangerous
from po-
tentially dangerous human presence. In developed areas
cubs may learn this behavior early from their mother.
The attitude toward chamois, roe deer, and cows was
indifference or curiosity. Once a chamois group ran away
startled and once a roe deer looked alarmed and barked
near them; the cubs always ran away and hid in bushes,
suggesting an interspecific recognition of alarm signs.
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