This question was earlier asked by Devaraja Indra to lord Brihaspati.
He asked about the characteristics of all the yugas.
Devaguru answered the question as follows.
(I'm only quoting the part of krta yuga)
10-18. Kṛta Yuga is said to consist of seventeen lakh twenty-eight
thousand years, when Janārdana remains white in colour, and Dharma has
all its four feet intact. (Then) the earth is full (in all respects).
The people are devoid of lust and anger, fear and hatred. All people
are long-lived with quiescent souls and full control over the
sense-organs. They are as tall as five Tālas (Palms). They are
brilliant and well-informed. Men’s childhood extends to sixteen
thousand years. Thereafter the youth extends to thirty-two thousand
years. It is only thereafter that old age befalls men slowly. The
ultimate life span is one lakh years. In certain cases it extends even
From here, he tells especially about the livelihood of people and environment of krta yuga.
All living beings, animals, birds and beasts speak the
divine language. They are not mutually inimical. Serpents sport about
along with mongooses, cats along with mice, deer with lions, and owls
with crows. Even without being cultivated, the earth (though not
ploughed) produces much vegetation consisting of cereals, pulses,
barleys etc. They are tasty and able to accord strength and
nourishment. The trees bear fruits in all the seasons with excellent
flowers and fruits, good leaves etc. They are devoid of thorns and
they resemble Kalpa trees.
19-29. Cows yield the desired tasty milk at all times. The butter and
ghee produced from it is enormous. No woman becomes a widow there, nor
an unfortunate wretch. There is no Kākavandhyā (a woman with but one
child) there bereft of sons. There is no woman without virtue (all
women are virtuous). Birth and death befall men in due order. A father
never sees death of his son. People who die do not become ghosts. No
one is compelled to stay in Naraka. No one suffers pain due to
sickness. All Brāhmaṇas are well-versed in Vedānta. They regularly
study their Vedic Mantras. They are delighted in expounding the Vedas
and well-versed in the knowledge of Brahman.
Kṣatriyas make one of them the king with great devotion and loyalty.
They enjoy the earth righteously following his behests.
Vaiśyas are engaged in the various activities befitting the Vaiśya
community such as breeding of cattle, buying and selling of
O most excellent one among Suras, Śūdras are extremely faithful. They
do not do anything except service unto Brāhmaṇas and twice-born ones.
No one is base-born there nor is there anyone of mixed caste. No
impure one and no one of the fifth caste is to be seen there on the
Men there perform Yajña (Fire-worship), Yajana (Yajña on behalf of
others), Dāna, Vrata, Niyama etc. and pilgrimage without any
expectations of personal benefit thereof.
From this description, we know the livelihood of people and environment in krta yuga.
Source: Skanda Purana- Nagara Khanda- Chapter 27: Characteristics of the four yugas