In a discussion about various aspects of sleep, the Talmud today discusses equine sleeping patterns:
סוכה כו, ב
אָמַר רַב: אָסוּר לָאָדָם לִישַׁן בַּיּוֹם יוֹתֵר מִשֵּׁינַת הַסּוּס. וְכַמָּה שֵׁינַת הַסּוּס — שִׁיתִּין נִשְׁמֵי
Rav said: It is prohibited for a person to sleep during the day longer than the duration of the sleep of a horse. [One who sleeps for longer is derelict in the study of Torah.] And how long is the duration of the sleep of a horse? It is sixty breaths long.
Elsewhere, Rabbi Zeira extols the virtues of sleeping like a horse at night. It is what King David did.
ברכות ג, ב
רַבִּי זֵירָא אָמַר: עַד חֲצוֹת לַיְלָה הָיָה מִתְנַמְנֵם כְּסוּס, מִכָּאן וְאֵילָךְ הָיָה מִתְגַּבֵּר כַּאֲרִי. רַב אָשֵׁי אָמַר: עַד חֲצוֹת לַיְלָה הָיָה עוֹסֵק בְּדִבְרֵי תוֹרָה, מִכָּאן וְאֵילָךְ בְּשִׁירוֹת וְתִשְׁבָּחוֹת
Rabbi Zeira said: Until midnight, David would doze like a horse, [as a horse dozes, but never sleeps deeply]. From midnight on, he would gain the strength of a lion. Rav Ashi said: Until midnight, he would study Torah, as it is written: “I rose with the neshef and cried, I hoped for Your word,” and from midnight on, he would engage in songs and praise, as it is written: “At midnight I rise to give thanks.”
To which the medieval French commentator Rashi add this observation
רשי שם
מתנמנם כסוס – עוסק בתורה כשהוא מתנמנם. כסוס הזה שאינו נרדם לעולם אלא מתנמנם ונעור תמיד
The horse never sleeps. Instead it naps and then always wakes
Most of us don’t keep horses, and so cannot judge what exactly is going on. So today, for all you non-horse owning folk, Talmudology asks: How do horses sleep?
An Introduction to Equine Sleep
The thing is, for a long time the way horses sleep has been a bit of a mystery. Then we developed all kinds of clever recording devices like EEGs that allowed us a harmless peek inside the brain of the sleeping horse. In his review of sleep patterns in the horse published in the September 1990 edition of Equine Practice, the veterinarian Theodore Belling wrote that “usually a horse falls asleep while standing and is in a drowsing state. The lids are partially open and the head hangs down at a medium level.” As the horse slips into a deep sleep known by its electric patterns as Slow Wave Sleep its head gradually gets lower and lower until the horse decides all is good, and while remaining asleep, actually lies down. Like this:
Once in this position, known technically as lateral recumbency, “the horse sleeps in short cycles or episodes, rather than one continuous interval, as it does in humans.” There is a short period of slow wave or deep sleep, usually lasting about five minutes, followed by a five minute paradoxical sleep, a stage also known as the rapid eye movement (REM) period. (When we enter the REM period, that’s when we dream.) The horse then enters another five minute slow wave cycle, and then wakes up. It slept for a total of about 15 minutes and will stay awake for another 45 minutes or so, before doing the whole thing again. The total sleep time of the horse is somewhere between 2.5-5 hours per night. Oh, and if you drive past a field with a horse sleeping in the day, there is nothing wrong. Some horses like to do that.
“Horses are neither diurnal nor nocturnal but have intermittent periods of rest and sleep during the day with most of their sleep happening at night, particularly when confined in a stall. Certain relaxing situations, such as grooming may even lead to episodes of sleep in normal horses. This is, perhaps, the equine equivalent of sleeping in class.”
EEG recordings from a pony. From From Andre Dellaire. Rest Behavior. Veterinary Clinics of North America Equine Practice 1986:2 595.
This basic outline has been confirmed in a number of other studies. A 2008 paper in Proceedings of the American Association of Equine Practitioners noted that “horses require far less sleep than most humans, averaging a total of only 3–5 h/day” though foals, being baby horses, sleep more per day than do the adults.
And so it turns out that the horse sleeps a lot less than might be expected. Here for example are the times spend awake or asleep in a few different species. The horse is the most wakeful of them all.
| Time Spent (Hours) in Wakefulness and Sleep States per Day in Domesticated Species | |||||
|---|---|---|---|---|---|
| Animal | Awake | Drowsy | Deep Sleep | Dreaming | Total Sleep Time |
| Cat | 10 | 2 | 8.5 | 3.5 | 12 |
| Dog | 11 | 4 | 6.5 | 2.5 | 9 |
| Swine | 11 | 4 | 6.5 | 2.5 | 8 |
| Sheep | 16 | 4 | 3 | <1 | 4 |
| Horse | 18 | 2 | 3 | <1 | 4 |
| From Andre Dellaire. Rest Behavior. Veterinary Clinics of North America Equine Practice 1986:2 592. | |||||
The Rav and Rabbi Zeira clearly knew about horses. The horse does indeed only take short naps, and these rabbis extol us to do the same. These are examples of a careful observation the natural world, from where many talmudic statements are derived. This might seem obvious, but it is not. As we have noted in the past, the rabbis didn’t always demonstrate an accurate understanding of the animal kingdom. Abayye thought that wild geese have a scrotum. But they don’t. And Rabbi Shimon ben Chalfta thought that ant colonies have kings. But they don’t. At the same time the rabbis knew much about the world that we had to rediscover. Like sound traveling further at night, or the periodicity of ‘Halley’s’ Comet.
So the next time you see horses lying in a field, or even dozing while standing, don’t disturb them. They are doing what comes naturally. Instead, do what the rabbis did. Observe, and ask: what can I learn from this moment?
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