# Function: expectedBrainMass()

[**lifecycle-kit**](https://jonbogaty.com/lifecycle-kit/api/readme/index.md)

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[lifecycle-kit](https://jonbogaty.com/lifecycle-kit/api/readme/index.md) / [bio-laws](https://jonbogaty.com/lifecycle-kit/api/bio-laws/readme/index.md) / expectedBrainMass


# Function: expectedBrainMass() {#function-expectedbrainmass}


> **expectedBrainMass**(`bodyMassKg`): `number`

Defined in: [bio-laws/lifeHistory.ts:121](https://github.com/jbcom/lifecycle-kit/blob/074e4e7b8038d3e2de9eb44c4b5b5aee0ef02b48/src/bio-laws/lifeHistory.ts#L121)

Expected brain mass for a given body mass.

Source: Jerison, H.J. (1973). "Evolution of the Brain and Intelligence."
Academic Press.

  Brain_expected = 0.01 × M^0.75


## Parameters {#parameters}



### bodyMassKg {#bodymasskg}


`number`


## Returns {#returns}


`number`