function yprime = LynxHare(t,y)
% yprime = LynxHare(t,y)
% t (time) is a scalar and y is a 2-vector whose components are
%            y(1) = hares(t)
%            y(2) = lynx(t).
%
% yprime is a 2-vector that is the derivative of y at time t.
% 
% The following parameters are rough estimates
a = 0.5;    % birth rate of hares
b = 0.02;  % death rate of hares, depends on interaction with lynx (how good are lynx at killing hares)
c = 0.4;    % death rate of lynx
d = 0.004;  % birth rate of lynx, depends on interaction with hares (how well do hares feed lynx)

yprime = [  a*y(1) - b*y(1)*y(2);...
           -c*y(2) + d*y(1)*y(2)  ] ;
