And cougars.
The difference is, the older woman is facing an ever smaller pool of available men in her age range, far harsher judgment from society and being female (arguably) more emotional damage to herself.
But, don't women in the "cougar" age range (40s, 50s, I think it is) have the same size pool of available men in their age range as do men in their 40s & 50s? The population doesn't really shift to more women than men until a significantly older age, because men still die younger (though the gap is closing).
I don't think older women are judged more harshly, either, to be frank. An average kind of single, middle-aged man doesn't get a lot more respect or attention than an average kind of single, middle-aged woman.