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RE: Speculative Reproductive and Social Behavior in Tyrannosaurids (speculation)


Nice? I knew I would catch s*** for using names =P. I wasn?t trying tell a story more than simply work out how the different generations would change as time went on. I had to do that otherwise it would?ve been too hard to keep track of who is who. I was also doing it to illustrate a point. If you notice, the youngest offspring at the beginning don?t reach maturity until long after their parents and most of their older siblings are dead. This is different from most animals today (accept insects). Dogs for example can have multiple litters and see all of them into adulthood because it only takes a year for a puppy to grow up. In nature, animals that have few offspring, that take a long time to mature, seem to be typically good parents with strong family bonds; primates, including us are a great example. Yet even humans have far longer life spans relative to the time it takes our children to reach sexual maturity. Imagine if you only lived to the age of 25 while still taking 12 to 13 years to reach sexual maturity! You would take darn good care of your kids while you have time and you would have to rely on your younger siblings and older children to care for your youngest kids when you die.


Another thing I noticed is that the pack would essentially have to work like a conveyor belt, with the older members reproducing shortly before they die and being replaced by next to oldest age group. It would be an advantage for females to be larger; otherwise an unrelated male could come in and wipe out half of the pack. This would be disastrous, because unlike lions, it would take 12 more years before the young are replaced, which would leave a huge gap in the pack and eliminate any benefit coming from a division of labor.


Lastly, there would be many cases of whole groups of juveniles of different ages being orphaned if their parents died early. This is unlike cats or dogs, where if the mother dies, only the litter she is caring for at that moment would die. Aside from division of labor, this would be another explanation of the allometrical changes seen in tyrannosaurs. It would be an advantage for the young to be fleeter footed, as it would allow bands of orphaned offspring to survive into maturity by catching prey that was too fast for the adults.

Now there is the possibility that they simply abandoned their young at an early age like crocodiles, but this would not explain why a group of many different ages were found together. With the osteological evidence for intraspecific fighting and even cannibalism in consideration, it would seem unlikely that unrelated animals would band together with younger and weaker members of the same species. Crocodiles and alligators for example will cooperate with similarly sized adults, but they will eat younger crocs if given the chance. Tigers will attack and sometimes eat other tigers, but will occasionally feed with and even hunt with related tigers. So once again, with this in mind it seems unlikely that unrelated tyrannosaurs of different ages and sizes would band together.


So I know it was a little strange, but I had to put together a sort of ?story? to make sense out of some of these ideas. So, instead of making fun of it, please share some of your own ideas on how this situation with their age would work with packing behavior.

Simeon Koning



From: Mike Taylor <mike@indexdata.com>
To: simkoning@msn.com
Subject: Speculative Reproductive and Social Behavior in Tyrannosaurids (speculation)
Date: Tue, 16 Jan 2007 09:43:43 +0000

Sim Koning writes:
 > [...] 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.

Meanwhile, Sandra (not knowing that Sebastian is really Angela after
her operation) takes the secret plans to Boris who in fact is acting
as a _double_ double agent and does _not_ intend to show them to
Hezekiah Ben Hamish, the Scottish/Jewish undercover Royal Canadian
Mounted Policeman.  Instead, while under the influence of prescription
tranquilisers taken to help him deal with his stressful day-job at the
indoor potato-market, Boris forgets to attend his woodwork class with
Mandy the hot girl from Accounts Receivable, and leaves the plans on a
No. 41 bus to Stoke Newington, where they are found by Commander Brant
Testosterone And His Pain Punchers.  Tune in next week to find out
what happens when Hezekiah accidentally lets slip to Angela the Pain
Puncher that Ross is in love with Rachel.

_/|_ ___________________________________________________________________
/o ) \/ Mike Taylor <mike@indexdata.com> http://www.miketaylor.org.uk
)_v__/\ "... and isn't it good to see Manchester United in red" --
Richard Keys.


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