Since very
early in my childhood I am absolutely fascinated by felids, from the domestic
cat to the lion, from the tiger to the black footed cat. And as my father
asked, even in those early days, what I would choose for a job, I always
wondered how I could get paid for just being around cats, the wild and the domestic
ones. Well, I succeed. As a Professor at Unesp, one of my most important
“duties” is to watch feline behavior. I already enjoyed different kinds of
scientific work with these wonderful animals. I searched for their foot prints
and other vestiges while tried to see them in the wild. I observed them in zoos
throughout my country and abroad, while videotaping them in order to see it later
again and again and so being able to understand what I was seeing. I chased
domestic ones in the nights of my small town to figure out what would they do
when outside our homes. I analyzed color, shape and size of their hairs to
build a key to tell between the Brazilian species when only small pieces of fur
or individual hairs are available. I even looked for DNA in those hairs.
In one of
those works observing felids in zoos, I came to the idea to use behavior as
character to reconstruct phylogeny. Studying phylogeny is to try to understand
how species are related to each other. As an example among rodents, it could be
said that the mouse is more close related to the rat than to the shrew. To
reach such a conclusion, one might compare bones, mostly the ones in the skull,
or the DNA of the in-group, the group of species one is interested in
reconstruct its genealogic tree, its phylogeny. Characters based in skull bones
or DNA are the most common ones. But proteins, ecology, soft parts morphology
and other can be used as well. Behavior is not so a common source of characters
because of out of date opinions shared by ancient scientists. But this is
turning and the use of behavior as character source for phylogeny is becoming
more and more usual.
In that
particular research, I observed adult domestic cats (Felis catus), that lived in colonies of, at least, four
individuals. I used data collected mainly in two colonies. The cats didn't belong
to any particular race, being just avoided the black cats, or very dark ones,
because of difficulties to visualize behavior. There was not gender distinction
when choosing the individuals.
The other feline species included in
that work were the Bengal cat (Felis
bengalensis), the Caracal lynx (Linx
caracal), the Serval (F. serval),
the Asian Golden Cat (F. temmincki) the Geoffroy's cat (F. geoffroyi) and the Onsila (F. tigrina). The nomenclature of felids
followed in that work is the one indicated by Gittleman’s Carnivore Bahaviour, Ecology and Evolution, from 1989. The data
were collected in videotapes done, mainly, in four institutions: Fundação
Parque Zoológico de São Paulo, Brazil; Zoologischer Garten Berlin and Tierpark
Berlin-Friedrichsfelde, both placed in Berlin and Zoologischer Garten der Stadt
Wuppertal, in Wuppertal, Nordrein-Westfallen, Germany. I also have done some
filming in the Zoos of Sorocaba, Brazil, and the one of Copenhagen, Denmark.
I choose to
use facial grooming as the source of behavior suited to phylogenetic analysis.
Considering both sides of the face, felids display no less then forty five
different grooming behavioral units, including parts of the anatomy like the
face itself, the tongue and the forearm (for the feline grooms its face with
the front paw after it have been licked by the tongue). These are some examples
of these behavioral units:
PLB
- Protraction of the tongue, down.
The animal
opens the mouth, protracts the tongue up to about 1/3 of its maximum extension
and, then, curves it down.
ZAB
- Forearm.
After PLB,
with the paw lifted up, with the palm turned to the internal side, the cat
moves the head in direction to the chest, touches the tongue in the base of the
forearm, moves the head frontward and the paw backwards, licking the forearm
along and, than, retracts the tongue
ZPH - Paw to eyes
Departing from
ZAB, without touching in the face with the paw, with movements of the head and
the arm, the paw goes by the superior lip, by the vibrissae and by the eye
until landing in the forehead area.
ZHV - Eye to
vibrissae
Departing from
ZPH, the paw touches the face and goes down, with movements of the arm and of
the head until the forearm reaches the superior position of insertion of the
vibrissae.
PLB, ZAB, ZPV
and ZHV are part of the mnemonic codes I used in that work. I got 29 ones, for I didn’t discriminate
between left and right sides of the face. All observed felid species display
them. And as all species showed the same grooming movements, it wasn’t possible
to use them to compare species. To do so, I studied in what sequence each
species used the different behaviors to clean its face. It’s important to say
that it’s not usual at all to use sequences in behavioral studies. Most
scientists use the frequency that the animal displays each behavioral unit.
This means that most scientists count how many times each behavior is showed by
the animal subject in a given amount of time. But to use sequences is
preferable because they are much less altered by the environment then
frequencies do. And different species showed different sequences in the facial
grooming while sticking to the same pattern among the different individuals of
the same species. So, using sequences is a kind of a little breakthrough of my
work. To extract sequences from the raw data, the behaviors observed in the
videotapes taken in zoos, is not so straightforward and thus, me and my
collaborators build a software based in a mathematic algorithm created by one
of us, the MrDiTree algorithm.
So, as the
characters used to reconstruct the phylogeny of the species studied being the
sequences of grooming behavioral units, I had the way compare them. And each
species had more sequences in common to another one then to the others. I
summed up all the sequences each one species shared with every one other and so,
using a dedicated computer program, I could tell the distance of relatedness,
the phylogeny, of the studied species. The result is the figure below:
It is a cladogram, a graphic outline used to
show a reconstructed phylogeny. What the cladogram tells is that, among the
observed species, the Caracal is closer related to Geoffroy’s cat than to any
other species in that work. They are sister species. The same can be said from
the domestic cat and the Bengal Cat. In this phylogenetic tree, the Asian
Golden Cat is closer to the clade that bonds Bengal and Domestic Cats. And the
Serval is closer to the former group. Onsila is isolated from any other species
or group of species, meaning that it is farther linked to the others.
Comparing
these results to Felid phylogenies proposed by other authors it can be seen
that part of this cladogram is not so diverse whereas other part is so. The
worst part is that Geoffroy and Tigrina are not together, since they are South
and Central American species and it is hard to believe that they do not share
the same evolutional step that lead to creation of the South and Central
American spotted cats group. One possible explanation for that result is that
the Onsila individuals I used in that work were from very different origins and
I think that at least some of them were hybrids between Onsilas and other felid
species. If I’m right in this, of course all grooming behavior sequences certainly
wouldn’t be that of pure Onsilas.
Well, this
only a brief summary of that work of mine. The whole story can be read at Japyassú
HF, Alberts CC, Izar P, and Sato T (2006) EthoSeq: a tool for phylogenetic
analysis and data mining in behavioral sequences. Behavioral Research
Methods 38:549-556.
I am now
interested in the evolution of social behavior among the Felidae. Like others,
I believe that the cat is not the only species of that Family that is apt for
domestication. I think that many other feline species would be domesticated if
the same circumstances that lead to the domestication of the cat had arisen to
them too.
So I am
proposing a questionnaire to the members of zoos in Brazil as well around the
World. In this survey I am asking about some particular behaviors felids
maintained by members may or may not display towards its owner or handler. Some
other information is also asked for. I will then be able to compare the results
with those of other similar surveys, done in a bit different research design
were the closer human/feline bond showed by zoo keepers members and their wild
cats wasn’t taken in account.
Responsável pelo texto:
Dr. Carlos Camargo Alberts
(Professor Assistente Doutor do Departamento de Ciências
Biológicas da FCL, Assis – UNESP
