Quão altos eram os pais de Hagrid?

Eu posso te dar um pouquinho mais de informação. Sabemos que Grope - irmão de Hagrid - é bem pequeno:

See, with giantesses, what counts is producin' good big kids, and he's always been on a bit on the runty side fer a giant - on'y sixteen foot -'

Harry Potter and the Order of the Phoenix - p.609 - Bloomsbury - Chapter 30, Grawp

'How big are they?' asked Ron in a hushed voice.

''Bout twenty feet,' said Hagrid casually. 'Some o' the bigger ones mighta bin twenty-five.'

Harry Potter and the Order of the Phoenix - p.377 - Bloomsbury - Chapter 20, Hagrid's Tale

Quanto ao pai de Hagrid, posso dizer ainda que quando Hagrid tinha cerca de sete ou oito pés de altura, seu pai era pequeno o suficiente para se sentar em seu ombro:

Hagrid got up, went over to his dresser, opened a drawer and pulled out a picture of a short wizard with Hagrid's crinkled black eyes, beaming as he sat on top of Hagrid's shoulder. Hagrid was a good seven or eight feet tall, judging by the apple tree beside him, but his face was beardless, young, round and smooth - he looked hardly older than eleven.

'Tha' was taken jus' after I got inter Hogwarts,' said Hagrid, croakily.

Harry Potter and the Goblet of Fire - p.395 - Bloomsbury - Chapter 24, Rita Skeeter's Scoop

A mãe de Hagrid era um gigante, cuja estatura média é de ~ 20 pés de altura, de acordo com Hermione GoF:

'Well, I thought he must be,' she said, shrugging. 'I knew he couldn't be pure giant, because they're about twenty feet tall.

Nós não sabemos nada sobre a altura do pai além da citação do GoF que você mencionou:

Tiny little bloke, my dad was. By the time I was six I could lift him up an' put him on top o' the dresser if he annoyed me

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