ORGAN WEIGHTS OF DUGONG DUGONTOSHIRO KAMIYA
Department of Anatomy, Faculty of Medicine, University of Tokyo, TokyoSENZO UCHIDA
Okinawa Expo Memorial Park Aquarium, Motobu, Okinawa

AND
TERUO KATAOKA
Toba Aquarium, Toba, Mie

When the International Ocean Exposition (1975) took place in Okinawa, two dugongs (Dugong dugon) were donated from Indonesian Government to Japanese
Government, but these died within a short period of 22 and 23 days after arrival.
With the permission of Philippine Government, three more dugongs were subsequently imported to Japan until recently and attempts were made to maintainthem. While two of these dugongs died, the remaining one still remains healthy in
Toba Aquarium, after two years record history of maintenance in May 1979, daily
renewing the record of maintenance of dugong in Ja pan. Apart from these, adugong cadaver was brought to Ja pan from Philippine for scientific studies. InJanuary 1979, moreover, a female infant dugong was caught by a fishing net in
the suburbs of Nago, Okinawa (26°32'N, 128°07'E) and an attempt was made tomaintain it, but death occurred 33 days later.
TABLE I. BODY AND INTESTINE LENGTHS AND THEIRRATIOS IN SIX SPECIMENS OF DUGONG DUGONSpecimennumberBody
length(m)Smallintestine
(m)

Large
intestine
(m)

Ratio

D-1
D-2
D-3
D-4
D-5
D-6

1.38
1.55
1.58
1.69
2.04
2.54

5.40
5.85
7.30
6.66
7 .13
9.60

8.80
7.45
12.46
12.70
12.25
14.50

10.3
8.6
12.5
11.5
9.5
9.5

We have conducted a biological survey and investigation on the cause of deathin these six animals. In the present paper, the organ weights in these six dugongs
and the ratio of each value to body weight was summarized in Table 2. Most ofthe organs were weighed fresh at autopsy, but some of them were weighed after
fixation in 10% formalin solution.
In addition, the length of the intestine (Table 1), and the photographs of
external appearance of main organs (Pl. I-IV) were given. The body length was
Sci. Rep. Whales Res. Inst.,
No. 31, 1979, 129-132

130

KAMIYA, UCHIDA AND KATAOKATABLE 2.
Specimen number
Body length
Sex
Body weight (at autopsy)
Body weight (at capture)
Locality
Brain
Spinal cordHeartSpleenLungStomach
Small intestine
Large intestine
LiverPancreas
Parotis

BODY LENGTH, BODY WEIGHT AND ORGAN

D-1
135.0cm
M47.0kg

D-2155.0cm
M52.2kg

Philippines(Luzon Isl.)

Philippines(Luzon Isl.)

160.0g (0.340)
107.0(0. 228)} 625.0(1.330)

675.0
18.0
50.0
55.0

(l .436)(0.038)(0.106)(0.117)

KidneyAdrenal160.0g (0.306)
9.0 (0. 0172)
425.0 (0.814)
495.0 (0 .948)

755.0
16.0

(1. 466)(0 .0306)

150.0
150.0
1.00.8(0. 287)
(0.287)(0.00191)(0.00153)

Thyroid
Thymus
Pituitary
TestisEpididymis

0.6* (0.000127)
3 . O* (0. 00638)
2. O* (0. 00426)

Ovary
Integument=(Blubber)

13,000.0 (27 .66)

* calculated from the value after preservation in 10% formalin solution.
Figures in parentheses indicate percentages of body weight.
defined as the length from the tip of the head to the tail base. The body weight
was recorded at the time of death. Since body weight undergone a considerable
variation according to the condition of maintenance, the body weight at the timeof capture was also described together. The detailed anatomical findings of theseinternal organs currently under investigation will be reported elsewhere in a morphological research journal.
ACKNOWLEDGMENTS

vVe wish to express our thanks to the Directors and staffs of the Kamogawa Sea
Sci. Rep. Whales Res. Inst.,
No. 31, 1.979

ORGAN WEIGHT OF DUGONG

131

WEIGHT OF SIX SPECIMENS OF DUGONG DUGON
D-3
158.5 cmF
76.5 kg

D-4
169.7cmM
80. l kg
Philippines(Luzon Is!.)

D-5
204.0 cmF
120.5 kg
155 .0 kg
Indonesia(Sulawesi Is!.)D-6
254.0 cmF
220.5kg
262.0kg
Indonesia(Sulawesi Is!.)

Okinawa
218. 0 g (0. 286)
40.0 (0.0528)

225.0 g (0. 280)

250. 0 g (0. 207)

250.0 g (0.113)

19.0(0.0362)29.0(0.0362)910.0
1,440.0
1,900.0
1,125.0
45.0(l .194)(l.889)(2.493)(I. 476)(0. 0591)

1, 780.0
40.0(2. 222)(0.0499)

263.0
260.0
I. 7
1.5
7.0

(0 .328)(0. 324)(0.00212)(0.00187)(0.00873)

25.5
45.5
49.0
0.6

(0.0335)(0.0597)(0.0643)(0.000787)

2.1(0.00262)

I. 2(0.00149)

265.0
18.0
900.0
950.0
l,950.01,800.02,600.0
1,650.0
50.0(0. 220)(0.015)(0. 747)(0. 788)(1.618)(l .494)(2.158)(I. 369)(0.041)500.0
28.0
1,650.01.450.0
4,250.0
4,000.0
4,450.0
3,150.0
45.0(0.227)(0.0127)(0. 748)(0.658)(l .927)(l .814)(2.018)(l .429)(0.0204)

350.0
320.0

(0. 290)(0.266)11.5(0.0095)

600.0
500.0
3.5
3.4
16.0(0.272)(0.227)(0.00159)(0.00154)(0.00726)

0.9(0 .00075)

0.9(0.000408)

12.0* (0.00544)
18,600.0 (24.41)

World, Toba Aquarium, Okinawa Marine Park Centre and Sunshine International
Aquarium for giving chance for material examination and to Prof. M. Nishiwaki
of University of the Ryukyus for his valuable advice.

Sci. Rep. Whales Res. Inst.,
No. 31, 1979

132

KAMIYA, UCHIDA AND KATAOKAEXPLANATION OF PLATESPLATE I
Fig. 1. Ventral dissection of the thracoabdominal viscera. Female, 204 cm length.
D: duodenal diverticulum G: gallbladder H: heart S: stomach
Fig. 2. Ventral aspect of the thoracic viscera. Male, 158.5 cm length. Arrowshows the left superior vena cava. A: arch of the aorta.
Fig. 3. Hemisection of heart of a 254 cm length, female. The deep interventricular sulcus is indicated by the arrow.
PLATE II
Fig. l. Stomach and proximal duodenum. Female, 204 cm length. Cg: cardiac
gland DI: left duodenal diverticulum Dr: right duodenal diverticulum 0:
oesophagus
Fig. 2. Visceral aspect of the liver. Female, 204 cm length. R: right lobe G:gallbladderFig. 3. Ventral aspect of intact pancreas. Male, 169. 7 cm length. C: cauda ofpancreas
Fig. 4. Digestive tract. Female, 158.5 cm length. C: cecum D: duodenal
diverticulum I: small intestine K: kidney L: liver LI: large intestine S:stomach
Fig. 5. Dorsal aspect of the spleen. Female, 204 cm length.
PLATE III
Fig. !. Ventral aspect of the right kidney. Female, 204 cm length. U: ureter
Fig. 2. Posterior view of the male reproductive tract and urinary bladder of a135 cm length. B: urinary bladder E: epididymis S: seminal vesicle T:testis U : ureter
Fig. 3. Ventral aspect of the adrenal gland. Male, 155 cm length.
Fig. 4. Visceral aspect of the right ovary of 254 cm length. The ovarian follicle
indicated by the arrow.
Fig. 5. Ventral aspect of the pituitary gland. Female, 204 cm length. X 5.5
PLATE IV
Fig. 1. Dorsal aspect of the brain.
Female, 254 cm length.
Fig. 2. Lateral aspect of the brain. Female, 254 cm length.
Fig. 3. Ventral aspect of the brain. Female, 254 cm length.
Fig. 4. Dorsal aspect of the spinal cord. Male, 135 cm length. C 1 ~Th 3 (left)
and Th4 -Th8 (right).
Fig. 5. Dorsal aspect of the spinal cord. Male, 135 cm length. Th 9 -Th13 (left),
Th14 -Th18 (middle) and Th19 -L 4 (right).

Sci. Rep. Whales Res. Inst.,
No. 31, 1979

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