Bhagavatapurana 5.17.12

5.17.12

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eṣu puruṣāṇām ayuta-puruṣāyur-varṣāṇāṃ deva-kalpānāṃ nāgāyuta-prāṇānāṃ vajra-saṃhanana-bala-vayo-moda-pramudita-mahā-saurata-mithuna-vyavāyāpavarga-varṣa-dhṛtaika-garbha-kalatrāṇāṃ tatra tu tretā-yuga-samaḥ kālo vartate //

12. In these (continents) men live ten times the full length of human life; they are like unto gods; they are as strong as ten thousand elephants; having an adamantine frame and strength, lasting youthfulness, and unimpaired joys they feel happy; at the close of their long course of great conjugal pleasures their wives show but once signs of pregnancy of a year's duration. There the character of time is like that of Treta Yuga.