on, and I suddenly realize that this is indeed the pattern expected from
an animal whose body dried out when the lagoon dried up: the liga-
ments shrink as the body dries out, curving the vertebral column into a
backbend. Could there be an entire skeleton?
Thinking again, I reject the idea. This place was clearly disturbed. I
have thoracic, lumbar, and caudal vertebrae, but no pelvis or hind limbs.
Much of this guy is gone. It is unlikely that erosion did that, because the
places where those bones would have been are undisturbed. Instead, I
suspect there were scavengers before the animal was buried. The dig
continues and, to my surprise, we find four fused vertebrae, the sacrum.
But the bone is not near the lumbar vertebrae as it would have been in
the living animal. Furthermore, it is smaller than the lumbar vertebrae,
and rust-red in color, not black. The edges are oddly and smoothly
worn, in a different way from the sharp breaks in the vertebrae, as if
someone knocked all the edges off before it was buried. It puzzles me as
I consider the option that this little red sacrum was in the belly of the
big black whale and is evidence of one whale eating another. At this
point, that is just speculation.
We excavate the hill with the pointed backs of our hammers, moving
along the entire edge where the skeleton is visible. On the side away
from the vertebrae, I encounter a flange of thick, black bone, the shape
and size of the visor on a baseball cap. We excavate around it carefully,
but I cannot figure out which part of the whale this is. Impatiently, I pull
162 | Chapter 12
at it, and it comes loose. It shows a break—it was attached to something
bigger, and I just broke it. That annoys me. We continue to excavate the
bigger thing. That takes a lot of time. It is deeply buried and hard to
access. We lie on our bellies in the muddy soil, the hot sun burning our
necks. Because the sediment is wet, our glue dries slowly, requiring
patience that I am unable to summon and which does nothing to
improve my mood. A larger black bone is finally exposed, bigger than I
expected, and with an unusual triangular shape. I suspect that this fossil
is unrelated to the whale vertebrae and that it is a skull of one of the
giant catfish that used to live here. Those are quite common, but they
are mostly ugly and gypsified fossils, and not very interesting paleonto-
logically. I move faster to get through this, but the bone does not coop-
erate. It makes me more impatient, so I just tug on the fossil. The big
black fossil suddenly comes loose. It is the size of a soccer ball, and I
fall backwards holding it in my hands. It is the braincase of a large
whale—the visor flange was the flange in the back of the skull where the
neck muscles attach. It is now also crystal-clear that I messed up: in my
impatience, I have damaged the fossil whale skull. Instead of pulling at
pieces and breaking them off, I should have slowed down, excavated the
soil around the fossil, and not pulled on the fossil until it was visible in
its entirety.
I sit down, mad at myself, mad at the black skull, and mad at most of
the rest of the world. After a drink of water and some cookies, my head
clears, and a new plan is hatched: limit the damage, be patient, and
excavate carefully. The braincase is well preserved, and I can see that
more of the specimen is still in the hill. Everything slows down now, but
we do it right, we remove overburden carefully, brush surfaces clean,
and let them dry before we glue them and continue with the excavation.
Eventually, much of a skull emerges, though somewhat gypsum-
encrusted, and deformed by burial forces forty-two million years ago.
The snout is complete, but it is waterlogged and the bone is soft as dust.
I excavate small parts of it with a dental scraper, let them dry, and then
harden them. Eventually the snout comes out, with lots of teeth in place.
We pick up many small bone pieces, and put them in bags. At home, we
wash all of them, and attempt to fit the smaller pieces to the big pieces.
All the big pieces fit together. This is a very different whale from the
with three cusps in a triangle on the upper teeth (figure 34). Above
the orbits is a thick flange of bone, the supraorbital process. Those
are features reported for a family of Eocene whales called protocetids,
Whales Conquer the World | 163
and this is the first protocetid of Kutch for which we have found a skull
with partial skeleton. We call it Dhedacetus. 3 Protocetids are rarer than
remingtonocetids, and given their size and the sacrum we just found,
might easily have been the predators of the smaller, fish-eating, reming-
tonocetids.
protocetid whales
Protocetid whales (figure 53) are found all over the world (figure 10) in
rocks between forty-nine and thirty-seven million years old.4 Their
predecessors (pakicetids, ambulocetids, and remingtonocetids) only
occur in India and Pakistan. It is thus likely that protocetids were the
first whales able to migrate long distances and colonize the world. Pro-
tocetids are also the ancestors of basilosaurids, and through that, all
later cetaceans, including the modern ones (figure 54).
Protocetids from India and Pakistan include a dazzling variety of
genera: Indocetus, Rodhocetus, Babiacetus, Gaviacetus, Artiocetus,
Makaracetus, Qaisracetus, Takracetus, Maiacetus, Kharodacetus, and
Dhedacetus. 5 In addition, Protocetus, Pappocetus, Eocetus, and Aegyp-
tocetus are known from Africa,6 and Georgiacetus, Nachitochia, Caro-
linacetus, and Crenatocetus from North America.7 Tantalizing frag-
ments of a protocetid have also been discovered in Peru.8 With so many
genera, protocetids are more diverse and more widely distributed than
any of the other families of Eocene whales.
More or less complete skeletons are known for only a few pro-
tocetids: Rodhocetus, Maiacetus, Artiocetus, and Georgiacetus (figure
55). Interestingly, forelimbs and hind limbs are missing in even some
of these relatively complete skeletons, such as Georgiacetus and our
Dhedacetus. It could be due to scavengers eating the cadaver, or because
the cadaver was floating in the ocean, with pieces falling off and sinking
as time progressed. With so many species for which no skeletons are
known, it is difficult to know how representative what we know is for
the entire group, but for now it seems that protocetids lived in the
oceans like modern sea lions: hunting fast-swimming prey and power-
ing their bodies with their limbs. However, they also had ties to the land,
and probably went there for functions related to reproduction such as
mating, giving birth, and nursing.
Feeding and Diet. Protocetids had powerful jaws and teeth, similar to
ambulocetids, and different from remingtonocetids. The teeth and jaw
164 | Chapter 12
figure 53. Life reconstruction of Maiacetus, a protocetid whale that lived in what is
now Pakistan around forty-seven million years ago. Protocetids were the first whales to
colonize the world’s oceans.
Whales Conquer the World | 165
Protocetid whales
millions of
years ago
Babiacetus
36
Basilosauridae
Carolinacetus
40
acetus
Eocetus
Georgiacetus
Remingtonocetidae
aisrQ
Protocetus
Gaviacetus
44
Artiocetus
Maiacetus
Rodhocetus
icetidae
Ambulocetidae
48
Pak
Indo-Pakistan
Africa
North America
figure 54. Relationships among some of the better-known protocetids. The basal
and older protocetids are Indo-Pakistani, but later ones are known from most of
the world’s oceans. Phylogeny from Uhen et al. (2011).
figure 55. Skeleton of the protocetid Maiacetus, modified after Gingerich
et al. (2009).
shape suggest that protocetids fought large and struggling prey. Isotopes
of the teeth indicate that their prey lived in the water.9 The protocetids
from the Eocene of Kutch are much larger than the remingtonocetid
whales that lived around them; as stated before, it is possible the latter
were protocetid prey.
166 | Chapter 12
At first glance, all protocetids have similar dentitions. The dental for-
mula is always 3.1.4.3/3.1.4.3. Upper molars have two large cusps and
sometimes one additional cusp on the side of the tongue. Lower molars
have a high trigonid in the front and a low talonid in the back, each with
a single cusp (figure 34). In spite of that general similarity, there is ample
evidence for dietary specialization between different protocetids. Most
genera are like Kharodacetus: they have slender and high teeth with sharp
edges and the distinct phase I attritional facets that characterize all early
whales.10 Babiacetus is different. The molars are more blunt and are worn
apically, which implies heavy tooth–food–tooth contact. In one of the
Indian Babiacetus specimens, one tooth in each left and right jaw are bro-
ken and only stubs remain. The two broken teeth are across from each
other, and it is possible that both broke during the same violent jaw-clos-
ing event. Abrasional wear surfaces on both of these teeth indicate that the
teeth were used after they broke. That means that the whale survived the
damage. Unlike most protocetids, the left and right jaws of Babiacetus are
fused with each other as far back as the second premolar.11 This gave the
animal a very powerful jaw, also suggesting that it fought even stronger
prey than other protocetids. The ubiquitous marine catfish from Kutch
have very hard, bony heads and may have been a prey item for Babiacetus.
The shape of snout and palate among protocetids varies greatly,12
and those differences probably reflect dietary specializations, but this
has not been studied in detail. The strangest protocetid face is certainly
that of Makaracetus,13 which has jaws that are not straight, but bent
down. It certainly fed very differently from other protocetids, but we do
not know on what or how.
Smell and Taste
Like the earlier whales, protocetids had a sense of smell. The olfac-
tory organ of mammals picks up chemical compounds that are air-
borne, not those that are waterborne. It does this by trapping airborne
molecules in the mucus on the inside of the nasal cavity, where these
molecules stimulate neurons (nerve cells) that are part of a large nerve
called cranial nerve 1, the olfactory nerve. These neurons send their
findings to the brain via another nerve, the olfactory tract. Among
modern cetaceans, olfaction is well developed in mysticetes14 but ap-
pears to be rudimentary or absent altogether in odontocetes.15 It is
not clear why modern cetaceans use their sense of smell. Some mod-
ern whales (in the family Balaenidae, the so-called right whales) may
detect the airborne scent of krill, which smells like boiled cabbage, to
Whales Conquer the World | 167
find their food. They have been observed to swim upwind when the
smell of krill is in the air. The skull of the early whales indicates that
members of this group had a sense of smell: there are small bony per-
forations for the olfactory nerve and a long bony tube for the olfactory
tract in protocetids,16 and the same is also true in remingtonocetids
(figure 35) and basilosaurids.17
Olfaction in mammals is very different from taste. Taste receptors
in mammals are mostly located on the tongue and palate. They are
designed to detect chemical compounds suspended in a solid or fluid
medium, and these signals are passed on to the brain via cranial nerves
7, the facial nerve, and 9, the glossopharyngeal nerve. Unfortunately,
those cranial nerves do not have taste tracts that run in bony canals,
and can thus not be studied in fossils.
There is a third chemical sense in mammals. The vomeronasal or-
gan, also called Jacobson’s organ, is located on the floor of the nasal
cavity. It consists of a small sac that can detect large flavorant mol-
ecules through a duct that opens on the front of the palate. Not all
mammals have a vomeronasal organ; humans lack it, for instance. In
animals that have it, dogs for instance, the slit-like openings of its
ducts are visible just behind the upper incisors on the palate. The
vomer
onasal organ plays an important role in detecting pheromones,18
chemicals that are signals for other animals of the same species, such
as those involved in sexual communication. In some artiodactyls, the
vomeronasal organ is used to detect the reproductive status of conspe-
cifics. Male deer engage in a behavior called flehmen, where they raise
their head with open mouth, exposing the vomeronasal ducts on the
palate to the air that, hopefully for the deer, carries molecules indica-
tive of nearby females in estrus.19 Like olfaction, the vomeronasal or-
gan signals the brain via cranial nerve 1, and is stimulated by airborne
molecules; but unlike olfaction, these molecules reach the organ via
the oral cavity and are transported through the two slits on the pal-
ate. To get from the mouth to the nose, the vomeronasal ducts pass
through two holes in the palate called the anterior palatine foramina,
or, sometimes, the incisive foramen. No adult modern cetacean has
a vomeronasal organ, and they also lack anterior palatine foramina.
However, anterior palatine foramina do occur in pakicetids. Given
that cetaceans are related to artiodactyls, it is likely that the vome-
ronasal organ was present in early whales. It was certainly lost when
whales became more aquatic—in remingtonocetids and protocetids
such as Kharodacetus—as indicated by the absence of anterior pala-
tine foramina in their skulls.
We can only speculate what Eocene whales used their sense of smell
for, but a reproductive function is possible. Sea lions have a sense of
smell, and there too, it is important in functions related to reproduc-
tion: identification of potential mates, and recognition of their own
young in a crowded colony.20
168 | Chapter 12
Vision and Hearing. A telling difference between protocetids and
basilosaurids on the one hand and pakicetids, ambulocetids, and rem-
ingtonocetids on the other is the position of the eyes. Protocetids and
basilosaurids have large eyes that face toward the side of the animal
and are located below a thick, flat piece of the skull, the supraorbital
shield (figure 52). These whales had excellent vision (unlike reming-