Dear Ben, The Torah clearly delineates the physical criteria for determining whether an animal is kosher or not. These are that it be a ruminant and have split hooves (Leviticus 11:2-8; Deuteronomy 14:4-8). The giraffe is not only the tallest cud-chewer but also has completely cloven hooves. It therefore fits the Torah criteria for being kosher.
Fatigue is defined as extreme physical or mental tiredness or exhaustion. An example of fatigue is what you feel after you run a 10-mile marathon. fatigue. fatigue.
An example of true weakness is being unable to lift something no matter how hard you try, although you may have been able to do so earlier. Fatigue means that with full effort, you can get the strength you need to lift something, but it may feel more difficult and tiresome to do so.