# What Is So Peculiar With 7, 14, 21, 28 In Relation To Bird's Incubation Period?

By EagleSpeed

@stbrians (12805)

Kakamega, Kenya

January 13, 2017 1:57am CST

They make a calender
Seven days make a week
Some take seven, others fourteen days to hatch eggs.
Yet some take twenty one and twenty eight.
How long does an ostrich take?
Who taught them to count?
How do they know the calender?
Or men aped them?
It amazes me.
Does it amaze you?

2 people like this

3 responses

@owlwings (39101)

• Cambridge, England

13 Jan 17

If what you say is, indeed, true, I suspect that the moon is involved here. Just as the moon and the sun together make the tides which follow a roughly 28 day cycle, so the tiny ocean which is inside an egg is also affected and adjusts its timing according to the truly minute pull of the sun and the moon on the embryo.
Even the human monthly cycle has a 28 day period, so it looks as though the mechanism which is behind all reproduction is very, very ancient.

3 people like this

@owlwings (39101)

• Cambridge, England

13 Jan 17

@magallon I did do some further calculation using the list given by Wikipedia (which is a little more detailed than the one you posted). Although the data is very limited, calculating the frequencies for exact multiples of 7 and other values where the remainder is 1 or 6, 2 or 5 or 3 or 4, it showed that the incubation periods for all four cases are evenly distributed and there is actually NO evidence of a preference for multiples of 7.

1 person likes this