buffalo data frame has 20 rows and 3 columns.
Cohort size and deaths for African buffalo from Sinclair (1977) as reported by Krebs (1989) in
Table 12.1, page 415.
This data frame contains the following columns:
number alive at start of each age interval
number dying between age interval X and X+1
Krebs, C. J. 1989. Ecological Methodologies. Harper and Row, New York, NY. 654 p.