The following parts are taken from PEU:1

> 
> **122.2 common or typical**
> 
> 
> We often use *can* to say what is common or typical. 
> 
> 
> 
> > 
> > Scotland can be very warm in September. 
> > 
> > 
> > Ann can really get on your nerves sometimes. 
> > 
> > 
> > 
> 
> 
> **345.2 'general' possibility: *can/could*, not *may/might***
> 
> 
> We normally use *can/could* to say that things are possible in general: 
>  people are able to do them, the situation makes them possible, or there is 
>  nothing to stop them. *May/might* are not used in this way. 
> 
> 
> 
> > 
> > These roses can grow anywhere. (NOT ••• These roses may grow anywhere.) 
> > 
> > 
> > Can gases freeze? (NOT ••• May gases freeze?) 
> > 
> > 
> > In those days, everybody could find a job. (NOT ••• In those days, everybody might find a job.) 
> > 
> > 
> > 
> 
> 
> **339.10 another use of *may/might*: typical occurrences**
> 
> 
> In scientific and academic language, *may* is often used to talk about typical 
>  occurrences - things that can happen in certain situations. 
> 
> 
> 
> > 
> > A female crocodile may lay 30-40 eggs. 
> > 
> > 
> > The flowers may have five or six petals, pink or red in colour. 
> > 
> > 
> > Children of divorced parents may have difficulty with relationships. 
> > 
> > 
> > 
> 
> 
> With this meaning, *might* can be used to talk about the past. 
> 
> 
> 
> > 
> > In those days, a man might be hanged for stealing a sheep. 
> > 
> > 
> > 
> 
> 
> 

These explanations made me puzzled. Since they can both relate to typical occurrences, is it possible to substitute *can/could* for *may/might* in PEU 339.10 if the context is not written in scientific and academic language?

1. PEU = Michael Swan's, *Practical English Usage*.