[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
Speculative Reproductive and Social Behavior in Tyrannosaurids (speculation)
Some interesting things come to mind when you consider both the estimated
life span and the possibility of pack hunting in tyrannosaurs. The life span
of tyrannosaurids is estimated to be between 25 to 30 years years, with
sexual maturity being reached possibly within the 4 year rapid growth period
(12 to 16). This would mean that the young would reach sexual maturity at
about the same time their parents die of old age. With this in mind,
consider this (highly) hypothetical scenario based on the multiple
Albertosaur specimens found together and described by Currie et al.
-Note- This is purely a fun intellectual exorcise on my part and an attempt
to logically sort out one possible scenario for pack hunting tyrannosaurids.
I also gave them names so this would be less confusing to the reader.
We have 10 Albertosaurs in a pack; 2 of them represent fully grown
sexually mature sisters, both 21 years old, we will call them Sue and Jane.
There is also an unrelated 17 year old alpha male which mates with the 2
females, we will call him Stan. There are 4 sub adults just reaching puberty
from a younger clutch related to Sue and Jane, each of them are about 13
years of age; they consist of 3 males and 1 female. The 3 sub adult males
are Phil, Bob and John, the female is Lisa. The sub adults assist Jane, Sue
and Stan in hunting and with the care of their young, much like some birds
of prey do today. Lastly there is a small 10 year old male named Tinker and
two 2 year old males named Mike and Ike, the last 2 are the only surviving
offspring of Sue and Jane.
Siblings or Cousins
Only surviving offspring of Sue and Jane
Mike & Ike 2
3 years pass, Sue and Jane die. Sue dies in a territorial dispute with a
Daspletosaurus and Jane is killed from a disastrous trip and fall while
chasing a hadrosaur, they have 6 more offspring before they die. Tinker, now
13, fills the sub adult role in the pack. Phil, Bob and John are now adults
at 16 years of age; they leave to find their own mates while Stan mates with
Lisa, they have 8 offspring together. Mike and Ike are now 5.
4 more years pass and the aging 24 year old Stan is killed by a healthier
19 year old named Thomas. Thomas mates with the now 20 year old Lisa and
drives away Tinker who moves on to find his own mate. Lisa is able to
protect her dead sisters' offspring, as well as her own, from Thomas with
her larger size and greater strength. 3 of her sisters' 6 offspring have
died and the rest are now 6 years old, 4 of her own young have died and the
rest are now 4. Mike is eaten by a crocodile and Ike is now 9.
7 years pass, Lisa and Stan die and Ike is now 16 and almost fully grown.
Mike is left with his siblings and cousins, 3 of which are 13, 4 are 11 and
several more are under 10. Mike leaves to find a mate and is replaced by an
18 year old unrelated male, which mates with 2 of the young 13 year old
females while he kills or drives away the males. A few of the orphaned young
males manage to survive into adulthood by banding together in a bachelor
pack while using their greater speed and maneuverability to catch prey too
fast for the adults. The cycle continues?.
Now you?ll have to forgive me if I made a mistake somewhere in there, but
the point was to illustrate the fact that adult tyrannosaurids would have a
rather limited time to breed and raise their young to adulthood. In fact
they would hardly have time to see their first clutch reach maturity. This
would seem to be good motivation for parental care, as well as sibling care.
Once the oldest members of the pack die, pack leading duties might have been
taken over by the younger females, while the males left in search of
Again, I know this is all pure speculation on my part. Let me know if any
of you have any ideas on how a parental care and pack behavior might work
with their relatively short adult life spans in consideration.
Get live scores and news about your team: Add the Live.com Football Page