The Shiba Inu cryptocurrency is now the world's 20th-biggest by market value and has more than tripled in the past week, partly fueled by Elon Musk's latest tweet about his own puppy.

Meanwhile, animal spirits are stirring again for bitcoin after the token surged more than 30 per cent in the past seven days to the highest since May.

The rally contrasts with the more pedestrian recent performance of traditional assets. Bitcoin was 5 per cent higher at $54,079 as of 10:13 am in New York, about $9,331 shy of its mid-April all-time high.