PARKER — THE FLORIDA MANATEE 
129 
The three manatees at the Miami Aquarium were of very different 
sizes so that they were easily distinguishable. The largest one was a 
female of about three meters in length. The next in size was a male 
about two and a quarter meters long. And the smallest was a young 
one of undetermined sex somewhat less than two meters from snout 
to tail. In the late afternoons these three animals were commonly 
found l5dng nearly parallel one to the other and exhibiting no other 
motion than the occasional respiratory one already described. Under 
such circumstances continuous records could be kept of the breathing 
of the animals for periods well over an hour. Each set of records 
included the lengths of time covered by the breathing periods, the 
number of breaths in each period, i.e., the number of times the nostrils 
were brought to the surface and opened and closed, and finally the 
resting periods or lengths of time each manatee remained quietly 
resting under water. The details of three such sets of records, each 
covering about an hour, are given in table 1. 
It is evident on inspecting table 1 that in all three sets of records 
the young manatee came most frequently to the surface to breathe, 
the male less frequently and the female least frequently. The details 
of this table are, however, best appreciated by a comparison with table 
2 which gives in compact form the general averages from table 1. 
On comparing these two tables it will be seen that the breathing 
period in the young manatee varied from 20 seconds to 3 minutes and 
averaged 49 seconds. In the male it ranged from 20 seconds to 3 
minutes and 20 seconds and averaged 1 minute. In the female it ran 
from 20 seconds to 3 minutes and averaged 1 minute and 17 + seconds. 
Although the range in the length of the breathing period is much the 
same for the three individuals, table 1 shows that short periods are 
more characteristic of the young, longer ones of the male, and still 
longer ones of the female. 
The numbers of breaths taken in the breathing periods by the three 
manatees vary in each instance between 1 and 4 except that there is 
one record of 5 in the breathing of the male. Nevertheless table 1 
shows that the young takes a smaller number of breaths, average 
1.7 — , than the male, average 2.2, and the male a smaller number than 
the female, average 2.6. 
Although it is true that the young manatee came to the surface 
more frequently than the male and the male more frequently than 
the female, and, further, that the young one took fewer breaths per 
period than the male, and the male than the female, it is also true that 
