Monkeys are part of the Order of Primates, a group of
mammals that include prosimians (like lemurs), and anthropoids (like monkeys, apes and
humans). Primate-like mammals (proto-primates) probably begin to emerge in the
Paleocene Epoch in the Tertiary Period (after 65 million years ago. This is the
beginning of the Cenozoic Era(Age of Mammals and Birds), but there may have been some
primate-like animals in the Late Cretaceous (prior to 65 million years ago, the
Cretaceous is the last period of Mesozoic, the age of Dinosaurs it is when you get the
Raptors and the T-Rex).
The first proto-primatesmwere small
and probably closely resembled the modern tree shrew. True primates (Prosimians) seem
to have emerged in the Eocene Epoch circa 55 million years ago. Modern Prosimians
include Lemurs, Tarsiers and Lorises. Most of the living prosimians can be found on
Madagascar and they are nocturnal (active at night) unlike Monkeys which tend to be
diurnal (active during the day).
The ancestors of modern
Monkeys split off from Prosimians forming the suborder anthropoidea. This occurred in
the Late Eeocene or Early Oligocene (circa 40 million years ago) but the record is
sketchy. These are not the monkeys we see today but ancesteral forms. New World
Monkeys (Platyrrhine) split off from Old World Monkeys (Catarrhine) , around 30 million
years ago. All of the Monkeys from this period are
extinct.
Monkeys are thus a branch of the same suborder of
Primates as humans and apes. Apes split off from Monkeys during the Miocene some 21
million years ago. The hominids (ancestors of humans) split off from apes between 5-8
million years ago during the late Miocene/Early
Pliocene)
Prosimians and Monkeys declined during the
Miocene and there was an explosion of apes. Monkeys later made a recovery and became
ultimately more successful than apes, radiating into many
forms.
Monkeys did not stay still, but continued to evolve
down to the modern age. So the modern monkeys should be regarded as PRIMATE COUSINS to
apes and humans and not ANCESTORS.
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