Abstract 
At the beginning of February 2000, during the monthly ultrasound check-up 
of a 30+ year old Tursiops truncatus in Zoomarine, Portugal, it had been confirmed that 
she was having a twin gestation. This unusual and infrequent situation yielded quite some 
reactions and plannings. We were early enough in our diagnosis to have time to prepare 
correctly, the birth estimation, if the animal would go full term, being between Oct 30th and 
Nov 4th, 2000. Contacts were taken with people who have had similar cases, the best known being 
the twins from Kolmarden, Sweden in 1990. Our female didn't have a good history for her latest 
gestations and this, coupled with her getting older, was a reason for extra concern. Also, 
another female was pregnant at the same time, with the expected birth date in her case to be 
between Aug 21 and 31, 2000. Several protocols were developed: daily observations by trainers 
and students, including measurements and twice daily temperature; veterinary protocols for best 
and worse situations; management protocols (separation of animals, night work, possible 
construction of an "elevating" platform in one of the pools). Frequent ultrasound check-ups were 
performed to control the good development of the gestation, with both foetus developing at the 
same rate. Her last ultrasound happened on July 20th. On the July the 23rd, a drop of one degree 
in her body temperature lead us to separate her. She showed frequent contractions during that 
night, but stayed very calm, and started her abortion in the early morning. After two hours of 
unsuccessful expulsary contractions, an injection of 30 UI of ocytocine was administered by 
voluntary behaviour. Twenty minutes later she expelled the first foetus, and the second followed 
after another 3 minutes. They were both males and appeared to have been sharing the same 
placenta. The animal quickly recovered from her abortion.