Cayot, Linda J.

English

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1991 NOTICIAS DE GALAPAGOS 5
Once a single tree has become established, is it
doomed to leaveno descendants? We thoughtitwould
be doomed because from 1978 to 1982 we found
seeds beneath the single tree on Genovesa, but never
a sapling. It would have been legitimate to conclude
after 5 years of observation that Erythrina velutina
was self-compatible (in being able to produce seeds)
but that progeny were inviable. And our conclusion
would have been wrong! In July 1983 there were
nine small saplings growing beneath the tree ranging
from 15 to 30 cm in height. Evidently the more than
2,400 mm of rain which fell that year (Grant and
Grant 1989) were sufficient to germinate at least a
few of the seeds. Seven were present the following
(dry) year and five were present in the drought of
1985. We have visited the siteeveryyearsince 1987,
each time finding two were alive. Both survived to
1991 and were healthy and in bud in February. One,
20 cm tall, stands under the canopy of the parent, 1.5
m from its trunk. The other, 35 cm tall, stands just
beyond the canopy 4 m from the trunk.
The parent tree on Genovesa is old. Thirty-five
rings were counted in a dead branch 1ess than 2.5 cm
in diameter; thus, if one ring is laid down each year
the branch was at least 35 years old when it died.
Given the much greater diame ter of the tree trunk (48
cm at 0.5 m height), we can extrapolate 10a total age
of7oo years or more. This seems extraordinarily old
andneeds to be verified. Tree-ring studies (e.g., Grant
1981) would help to determine if the reasoning is
plausible. At the moment the tree stand s 6 m tall,
produces leaves and seeds each year, and looks basi-
cally healthy. If it dies before its offspring do, then
it may be replaced by two, and very gradually a pop-
ulation may build up.
We suppose this happened on the even more re-
mote and apparently inaccessible Islands ofW olf and
Darwin. A single seed reaching one of these Islands
by sea, being transponed to the flat region on top, and
germinating, seems improbable enough. Two seeds
establishing themselves is even less likely. Never-
theless a single colonization assisted by a bird,
followed by multiplication, would explain the puzzle
of Erythrina trees on these remote Islands in the
Archipelago.
LITERA TURE CITED
Faegri, K., and L. van der Pij1. 1971. The principles
of pollination ecology. 2nd edition. Pergamon
Press, New York.
Grant, B.R., and P.R. Grant. 1989. Evolutionary
dynamics of a natural population: the Large Cac-
tus Finch of the Galápagos. Universi ty of Chicago
Press, Chicago.
Grant, P.R. 1981. Population fluctuations, tree rings
and climate. Noticias de Galápagos 33:12-16.
Grant, P.R., J.N.M. Smith, B.R. Grant, I.J. Abbott,
and L.K. Abbott. 1975. Finch numbers, owl pre-
dation and plant dispersal on Isla Daphne Major,
Galápagos. Oecologia 19:239-257.
Wiggins, I.L., and D.M. Poner. 1971. Flora of the
Galápagos Islands. Stanford University Press,
Stanford, California.
Peter R. Grant, K. Thalia Grant, and B. Rose-
mary Grant, Department of Ecology and
Evolutionary Biology, Princeton University,Prin-
ceton, New Jersey 08544-1003, USA.
THE PASSING OF TWO BELOVED REPTILES:
ONAN AND CHIQUITA
By: Linda J. Cayot
ANOBITUARYFORATORTO~E
The most individualistic, ornery, beloved tonoise
in Galápagos died early last year. Onan, an ancient
male tonoise, lived alone for most of this century in
the central crater of Isla Pinzón. As a result of the
overexploitation of tonoises in the 1800s and early
19OOs,the tonoise population on Pinzón fell to dan-
gerously low levels. The tonoise surveys in the 1960s
showed less than 200 tonoises were 1eft on Pinzón,
and all but Onan lived on the outer western and south-
ern slopes. In the central crater, Onan reigned alone.
Onan spent so many years alone that he began
exhibiting amorous intentions with tonoise-shaped
rocks. During a visit to Pinzón in 1970 by Craig
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NOTICIAS DE GALAPAGOS No. 50
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Figure 1. Onan was always alcrllO intruders enlcring his arca and would do his
ulmOSl, for a lurlIe, lo stand tall and control Lhe siluation (pholograph by T.H.
FrillS). Onan siempre estuvo alerta de los trasgesores en su territorio. manteniéndose
en pie y haciendo lodo lo posible por controlar la sÍluación.
'".,
MacFarland and Peter Kramer, Onan's special rock-
loving behavior was discovered. MacFarland named
him "Onan" after the biblical character.
During the past 20 years, as part of the rearing and
repatriation program runjointly by the CDRS and the
GNPS, nearly 300 young tortoises have been repatri-
ated to Pinzón, many of them to the central crater.
Thus, Onan spent his last two decades in the company
of many young tortoises.
Onan usually greeted the scientists and wardens
visiting Pinzón's central crater, approaching with his
mouth wide open and his head held as high as possible
(Fig. 1), an aggressive posture typical of antagonistic
interactions between tortoises competing for food,
water, shade, or mates. Reaching for his maximal
height, he would often lift one of his front feet and
totter momentarily with a tripod stance. He was not
large, but he stood tallo Ifyou raised your hand or head
above his or gently tapped him on the head, he would
submit by withdrawing, at least for a momento He was
difficult to photograph because he walked straight at
the camera, sticking his head right into the lens. One
strategy was for the photographer to lie on the ground
and snap the photographs just before being overrun by
the tortoise.
Onan looked ancient, with little extra flesh on his
.
bones and a scarred carapace cov-
ered with lichens. In his fmal years
he was nearly deaf and blindo His
presence on Pinzón made every
visit to that Island special for all
who had encountered him before.
He was last seen alive during the
tortoise census ofFebruary 1990.
Then, on a trip 4 months 1ater,
Washington Tapia, German Mo-
rillo, and Gayle Davis found his
remains.
By the tum of the century, rats
were so abundant on Pinzón that
Rollo Beck concluded that all
hatchlings wereconsumed byrats.
If so, the possibility exists that
Onan was a product of the 19th
century, one of the last generations
produced before rats took over
Pinzón. As to his exact age, no
one knows for sure, but he was a true patriarch, likely
well over 100 and possibly over 150 years old.
Onan was buried on Pinzón on 4 June 1990 and
he shall remain there as a part of his Island. Future
trips to Pinzón will not be the same for the Park
personnel, Station biologists, and other scientists who
knew him. We will all miss him.
AN OBITUARY FOR AN IGUANA
Chiquita, the unofficial mascot of the CD RS, died
on 25 Apri11990. In the early days of the Station, a
young land iguana was found roaming the grounds.
When Doña Magdalena Velez began working in the
dormitories in 1965, she continually saw the small
iguana and named it Chiquita because of the igua-
na's smallsize. Chiquitalivedon toroamthe Station
grounds for more than 25 years (Fig. 2).
Doña Magdalena was Chiquita's best friendo In
the years that Doña Magdalena worked in the dormi-
tories (1965-82), Chiquita was most often found
there. Magdalena often sat on the ground and Chi-
quita approached closely, often climbing onto her
lap to be fed chocolates and bananas. Chiquita loved
to be scratched and would stand in the typical up-
right posture that some iguanas use to encourage
finches to remove ticks. After Magdalena retired,
Chiquita frequented other homes at the Station to
.
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1991 NOTICIAS DE GALAPAGOS 7
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Figure 2. The aging of Chiquita was evidenced in pan by a marked darkenin~ of her
pigmentation from hues of brown and orange in 1977 (above) 10 dull black ID 1986
(below; pho1Ographs by T.H. Fritts). La edad de Chiquita se pone en evidencia al
mostrar un marcado oscurecimiento en su pigmentación, desde matices marrón
anaranjado en 1977 (superior) a negro opaco en 1986 (inferior).
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receiveherdailyrations. (Of
course, she also ate native
vegetation.)
For many of us, Chiquita
was our f1rst encounter with
a land iguana. Often within
a day or two of someone's
arrival at the Station, she sur-
prised them by looking in the
screen-door of their dormi-
tory room.
Chiquita was found dead
in front of Cruz Márquez's
house (one of her favorite
hangouts in recent years) ear-
ly on 26 April. Unlike Onan,
she was autopsied; her liver
was found to have failed. Her
skeleton will become a part
of the museum collection at
the Station. We will miss
seeing her roarning around
the Station.
With the passing of Onan
and Chiquita and with the
f1rst record of hatchling tor-
toises on Isla Española
("grandchildren" of the na-
tive adults in captivity; see
artide this issue), we move
into a new era, with the hope
that current management
programs will continue to
protect Galápagos reptile
populations well into the next
century and the one afterthat.
Linda J. Cayot, Charles
Darwin Research Station,
Isla Santa Cruz, Galápa-
gos, Ecuador.


The passing of two beloved reptiles : Onan and Chiquita

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The passing of two beloved reptiles : Onan and Chiquita

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