International Giant Otter Studbook Husbandry and Management

Section 2
Breeding, Cub-Rearing Success & Privacy from Human Disturbances
A self-sustaining captive giant otter population has never been created. Very few zoos in the
world have had successful reproduction. In captivity P. brasiliensis does not appear to be
particularly difficult to keep, but successful rearing of offspring has been rare, as high cub
mortality exists world-wide and historically (Sykes 1997-99 & 1998/2002; Sykes-Gatz 2001 &
unpublished data, 2003). See Tables 2-3. From 1968 to 1997, seven institutions reported
captive giant otter births. Litter size (n=31; i.e. litter sample size) ranged from 1 to 6 cubs, with
a mean of 2.9 and common litter size of 2 cubs. Of 177 cubs born live at seven institutions
(born 1968 -1997), only 16.4 % (29) were successfully reared (i.e. survived to one year of age or
older). This is an 83% cub mortality rate. [In 2003 more detailed census records became
available, so the cub survival rate reported in Sykes-Gatz 2001 was updated and slightly
increased for current census records.] More detailed data available for 90 of those 177 cubs,
indicated that 53% died during the first week of life, while 50% of the cubs surviving to one
week, died before reaching four months of age. (See Graph 1.) Most of these deaths occurred
because parents, stressed by human disturbances, failed to properly care for their cubs. This
was the primary cause of death. These two main mortality phases show that different factors
were responsible; i.e. gross parental neglect in the first week (when most cubs were eaten or/and
not cared for properly) and medical illness either independent of or resulting from parental
neglect thereafter. Medical illnesses that were commonly reported when cub deaths occurred
were pneumonia, enteritis, malnutrition, and intestinal invagination (Trebbau 1972; Autuori and
Deutsch 1977; Flügger 1997; Brasilia Zoo; pers. comm.; Dortmund Zoo, pers. comm.). Many
of these illnesses were thought to be secondary causes of death that developed as a result of
parental neglect/cub abuse.
From 1968 to 1997, all of the zoos with successful parent reared litters, provided parents with
privacy and isolation/seclusion from human disturbances (visual and acoustic) and presence
(zoo staff and visitors) during cub-rearing. Either their management methods (which were only
discovered and carried out after the loss of many litters) and/or “exhibit design” permitted
privacy. (“Exhibit design” means that the enclosures were natural or semi-natural and
expansive, i.e. at least 600m² (6,458.4 ft²) or more in size, and the otters could dig their own
dens underground to keep their cubs in. For management methods provided see Chapter 2
Section 10 and for “exhibit designs” provided see Chapter 2 Sections 10 & 12.) This is the most
important management factor needed to help parents rear litters successfully. (Great emphasis
has been placed on this management method throughout this manual and its 1 st edition. See
Chapter 2 Section 10 and below under “Historical Overview” for information on this method.)
From 1998 to 2002, four zoos reported litter births (40 cubs were born live) (Sykes-Gatz,
unpublished report). Three zoos (Belem* and Brasilia in Brazil and Cali in Colombia) reported
successfully rearing cubs (i.e. 16 of their 23 cubs total, were reared to one year of age or older).
[*Both Museu Paraense Emilio Goeldi (Belem, Brazil) and Criatorio Crocodilo Safari (Belem,
Brazil), the private facility associated with Museu Goeldi, are referred to under “Belem”. The
breeding pair at Museu Goeldi was loaned to Criatorio Crocodilo Safari in 2001 where the pair
had one litter (in 2002) while they were held at this institution. The parents successfully reared
the one litter born at the Safari and they had successfully reared 2 litters born at Museu Goeldi.
Because the same pair gave birth to at least one or more successful litters at both of the two
aforementioned institutions, these institutions are associated, and no other breeding pairs were
known to be held at these institutions, these two institutions, except where noted, are counted as
one institution for all data within this manual and are referred to as “Belem”.] Inherited thyroid
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