Sorry I haven't posted on this topic until now I got tied up with work!
Rejecting the take-off at any time for other than a clear and simple obvious serious problem is a tough decision that we pilots may be faced with. For encounters with mammals we have not been provided with a great deal of information on the issue - because there isn't any. With so many mammal types with different behaviours and no requirement to test and/or certify aircraft for a mammal data there is a complete absence of data on what might happen and what we should do.
As far as mammal strikes go, while not as common as bird strikes they do occur and interestingly from the available data cause more damage. The issue though is available data - no jurisdiction that I have found in my research compels pilots to file a bird/mammal strike report. Hence we get only roughly 20% of the data. Many airlines and airports collect the data, but are reluctant to share the data with regulators out of concern over potential liability.
In North America the most commonly struck mammal is the Deer. The consequences of these deer strikes are severe including complete hull loss and death or severe injury of the flight crew. With the recent exploding deer populations in North America the data from incurance companies is revealing that there is rarely a day goes by that an aircraft is not damaged by a deer encounter.
Good story about the pig. Recently a crew landed at a Canadian airport and just as they were leaving the runway saw a 150+lb pig. Quite a saga to track it down, but it has been suggested that a Pigs On Runway Kill (PORK) program would solve the problem. There has also been great speculation on what the smeel would have been like if part of the beast was ingested in the engine - bacon?
A final point concerns small bird strikes - starlings. Be aware that these are birds that travel in very large flocks and carry out pre-roosting flights. If you run into one of these flocks you can be in big trouble. Starlings are very dense (large mass/small size - not stupid) and they will hit multiple engines. It should be noted that the worst bird strike accident was in 1960 whyne a Lockheed Electra turboprop struck a flcok of stralings. One engine was shutdown and the remaining engines lost power the aircraft crashed with the loss of 62 lives.
Richard