Now here, if anywhere, we must be on our guard. In attempting to detect traces of mirthful expression in animals we are exposed to a two-fold danger: that common to all observation of animal ways—a too anthropomorphic kind of interpretation; and that of mistaking in other beings, {157} whether human or sub-human, what we envisage as funny, for their conscious fun. It is eminently natural, when we do not screw ourselves up to the severely scientific attitude, to see signs of chuckling glee in animals. I remember how I watched somewhere in Norway, in the early morning, a magpie as he stood for some time ducking his head and throwing up his long tail, accompanying these movements with chuckle-like sounds; and how I found it exceedingly hard not to believe that he was having a good laugh at something, possibly the absurd ways of the foreign tourists who visit his coast. Yet, judged by the standard of scientific observation, this “natural” interpretation was scarcely satisfactory. Since our aim compels us to be scientific, we cannot accept common modes of interpreting the “mischievous” performances of animals. Many of a monkey’s tricks are “funny” enough; yet we may seriously doubt whether he enjoys them as practical jokes. His solemn mien certainly does not suggest it; but then it may be said that human jokers have a way of keeping up an appearance of gravity. A consideration of greater weight is that what looks to us much like a merry joke may be a display of the _teasing_ instinct, when this goes beyond the playful limit, and aims at real annoyance or mischief. The remark probably applies to some of the well-known stories of “animal humour,” for example, that of Charles Dickens about the raven. This bird, it may be remembered, had to share the garden with a captive eagle. Having carefully measured the length of this formidable creature’s chain, he turned to good account the occasion of the giant’s sleep by stealing his dinner; and then, the rightful owner having presumably woke up, made an impudent display of eating the same just safely outside the {158} eagle’s “sphere of influence”. This doubtless showed some cunning, and something of spite; but it is not clear that it indicated an enjoyment of the fun of the thing. That this teasing and playing of tricks by animals may now and again approach the human attitude of malicious mirthfulness is not improbable. A cat that “plays” with its captive mouse, half-pretending, as it seems, not to see the small thing’s hopeless attempt to “bolt,” may, perhaps, be enjoying something of the exultant chuckle of a human victor. So, too, some of the mischievous behaviour of a lively and imperfectly domesticated monkey, which a simple-minded sailor has brought to his mother by way of making her happy, may disclose a germ of the spirit of fun, of a malicious playfulness which is capable of enjoying its jokes as such.