International Giant Otter Studbook Husbandry and Management

Section 12
Weaning & Feeding Techniques for Weaning
The gradual change-over from feeding milk replacers to feeding a total fish diet is called
“weaning”. More research needs to be conducted to determine the most optimal age to start a
slow gradual weaning process. The information available indicates that a giant otter cub
should be around at least 2 ½ to 4 months old when fish is first introduced into its diet and
the weaning process is begun. The age at which each cub will first accept fish will vary
from individual to individual, although it seems that milk formula should be given to fulfill
100% of the giant otter cub’s nutritional needs until it reaches around at least 2 ½ months
of age. Not fulfilling 100% of the cub’s nutritional needs with a milk formula before this age
may cause health problems. As well, waiting too long to begin the weaning process may also
cause problems. When the weaning process was started with cubs that were around
approximately 2 ½ and 3 or 4 months old, those cubs were successfully reared (See Section 5).
Many wild-born orphaned cubs reared at the institutions that used this method have been
successfully reared (Lazzarini 1998 pers. comm.; McTurk/Duplaix pers. comm. 2004). Note:
the ages of the wild-born animals were estimated. At Hagenbecks Tierpark (Germany) giant
otter cubs, at approximately 8 weeks old, mouthed and played with fish that the mother brought
to them; although they only first started swallowing solid fish at 70 days of age (10 weeks old)
(Hagenbeck and Wünnemann 1992). Later reports explain that two cubs, that were captive-born
and handreared at Hagenbecks, ingested solid food at 3 months old, although it was found that
they could not digest the fish properly when they were this age. “The feces contained a lot of
undigested fat and protein and the enzyme level of chymotrypsin was much lower than in adult
animals” (Wünnemann 1995 b ). Wünnemann 1995 further reports, “At 70 days, the [giant otter]
cubs will start to swallow solid food, although they start playing with it a long time before this
time. However, they are dependent on their mother for at least four months [i.e. the first 4
months of the cubs’ life] and will continue suckling up to the age of seven months”. The cubs
continued nursing mother’s milk when they were around 6 1/2 months old, although only
insignificant amounts were obtained and it provided little nutritional value. The weaning
process can occur over a varying time period until the cubs choose to reject the milk formula
(Duplaix/McTurk & Wünnemann pers. comms. 2004). Cubs may choose to reject milk formula
from one, a couple, a few, or even several months after accepting fish within their diet for the
first time (pers. comms. of the handrearers listed within this manual). Sometimes they may also
reject milk formula from 2 to 3 weeks after they start to eat fish within their diet. Caution must
be taken although, as the offering of milk formula should not be eliminated or reduced in
amount too soon or problems may result.
Reports indicate that giant otters do not require milk to meet their basic nutritional needs when
they are at the age of around 6 ½ months and older (note: this does not mean that their needs can
not be met at an earlier age; see the paragraph above). At one institution, some handreared
otters although have been reported to drink some supplemental milk formula (i.e. in addition to
their fish diet), even up to 10 months of age and they were reported to be successfully reared
(Duplaix/McTurk, pers. comm. 2004). Handrearers should although take care that otters wean
themselves fully of all milk formula within a reasonable time period. It seems that by at least 6
½ months of age, and up to an age that does not exceed approx. 10 months [based on the
outcome of the handreared otters just mentioned above], the cub should be eating a total fish
diet and should no longer be drinking any milk formula (Duplaix/McTurk & Wünnemann pers.
comms. 2004). (Scientific research on the meeting of nutritional needs of handreared giant
otters at various ages should be conducted to establish scientific guidelines for the weaning
process.)
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